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71f47ed2e2
FOREIGN KEY constraints. At the moment, MySQL will rebuild the entire table and indexes when such constraints are added or removed, even though the constraints do not affect the storage format of the data.
1073 lines
28 KiB
Plaintext
1073 lines
28 KiB
Plaintext
create table t1(a int not null, b int, c char(10) not null, d varchar(20)) engine = innodb;
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insert into t1 values (5,5,'oo','oo'),(4,4,'tr','tr'),(3,4,'ad','ad'),(2,3,'ak','ak');
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commit;
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alter table t1 add index b (b), add index b (b);
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ERROR 42000: Duplicate key name 'b'
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alter table t1 add index (b,b);
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ERROR 42S21: Duplicate column name 'b'
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alter table t1 add index d2 (d);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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KEY `d2` (`d`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL d2 23 NULL 4
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select * from t1 order by d;
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a b c d
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3 4 ad ad
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2 3 ak ak
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5 5 oo oo
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4 4 tr tr
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alter table t1 add unique index (b);
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ERROR 23000: Duplicate entry '4' for key 'b'
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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KEY `d2` (`d`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add index (b);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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KEY `d2` (`d`),
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KEY `b` (`b`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add unique index (c), add index (d);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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UNIQUE KEY `c` (`c`),
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KEY `d2` (`d`),
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KEY `b` (`b`),
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KEY `d` (`d`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL c 10 NULL 4
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drop index c on t1;
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ERROR 42000: This table type requires a primary key
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alter table t1 add primary key (a), drop index c;
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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KEY `d2` (`d`),
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KEY `b` (`b`),
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KEY `d` (`d`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add primary key (c);
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ERROR 42000: Multiple primary key defined
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alter table t1 drop primary key, add primary key (b);
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ERROR 23000: Duplicate entry '4' for key 'PRIMARY'
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create unique index c on t1 (c);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `c` (`c`),
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KEY `d2` (`d`),
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KEY `b` (`b`),
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KEY `d` (`d`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL c 10 NULL 4
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select * from t1 order by c;
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a b c d
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3 4 ad ad
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2 3 ak ak
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5 5 oo oo
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4 4 tr tr
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alter table t1 drop index b, add index (b);
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `c` (`c`),
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KEY `d2` (`d`),
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KEY `d` (`d`),
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KEY `b` (`b`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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insert into t1 values(6,1,'ggg','ggg');
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select * from t1;
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a b c d
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2 3 ak ak
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3 4 ad ad
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4 4 tr tr
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5 5 oo oo
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6 1 ggg ggg
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select * from t1 order by b;
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a b c d
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6 1 ggg ggg
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2 3 ak ak
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3 4 ad ad
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4 4 tr tr
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5 5 oo oo
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select * from t1 order by c;
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a b c d
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3 4 ad ad
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2 3 ak ak
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6 1 ggg ggg
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5 5 oo oo
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4 4 tr tr
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select * from t1 order by d;
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a b c d
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3 4 ad ad
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2 3 ak ak
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6 1 ggg ggg
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5 5 oo oo
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4 4 tr tr
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL b 5 NULL 5
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL c 10 NULL 5
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL d2 23 NULL 5
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) NOT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `c` (`c`),
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KEY `d2` (`d`),
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KEY `d` (`d`),
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KEY `b` (`b`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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drop table t1;
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create table t1(a int not null, b int, c char(10), d varchar(20), primary key (a)) engine = innodb;
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insert into t1 values (1,1,'ab','ab'),(2,2,'ac','ac'),(3,3,'ad','ad'),(4,4,'afe','afe');
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commit;
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alter table t1 add index (c(2));
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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KEY `c` (`c`(2))
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add unique index (d(10));
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `d` (`d`(10)),
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KEY `c` (`c`(2))
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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insert into t1 values(5,1,'ggg','ggg');
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select * from t1;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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5 1 ggg ggg
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select * from t1 order by b;
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a b c d
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1 1 ab ab
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5 1 ggg ggg
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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select * from t1 order by c;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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5 1 ggg ggg
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select * from t1 order by d;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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5 1 ggg ggg
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `d` (`d`(10)),
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KEY `c` (`c`(2))
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 drop index d;
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insert into t1 values(8,9,'fff','fff');
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select * from t1;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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5 1 ggg ggg
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8 9 fff fff
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select * from t1 order by b;
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a b c d
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1 1 ab ab
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5 1 ggg ggg
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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8 9 fff fff
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select * from t1 order by c;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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8 9 fff fff
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5 1 ggg ggg
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select * from t1 order by d;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 3 ad ad
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4 4 afe afe
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8 9 fff fff
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5 1 ggg ggg
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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KEY `c` (`c`(2))
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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drop table t1;
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create table t1(a int not null, b int, c char(10), d varchar(20), primary key (a)) engine = innodb;
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insert into t1 values (1,1,'ab','ab'),(2,2,'ac','ac'),(3,2,'ad','ad'),(4,4,'afe','afe');
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commit;
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alter table t1 add unique index (b,c);
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insert into t1 values(8,9,'fff','fff');
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select * from t1;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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select * from t1 order by b;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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select * from t1 order by c;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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select * from t1 order by d;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL b 16 NULL 5
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `b` (`b`,`c`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add index (b,c);
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insert into t1 values(11,11,'kkk','kkk');
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select * from t1;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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11 11 kkk kkk
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select * from t1 order by b;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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11 11 kkk kkk
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select * from t1 order by c;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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11 11 kkk kkk
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select * from t1 order by d;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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11 11 kkk kkk
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL b 16 NULL 6
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
|
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1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
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show create table t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
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`c` char(10) DEFAULT NULL,
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`d` varchar(20) DEFAULT NULL,
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PRIMARY KEY (`a`),
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UNIQUE KEY `b` (`b`,`c`),
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KEY `b_2` (`b`,`c`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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alter table t1 add unique index (c,d);
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insert into t1 values(13,13,'yyy','aaa');
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select * from t1;
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a b c d
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1 1 ab ab
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2 2 ac ac
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3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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11 11 kkk kkk
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13 13 yyy aaa
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select * from t1 order by b;
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a b c d
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1 1 ab ab
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2 2 ac ac
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|
3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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|
11 11 kkk kkk
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13 13 yyy aaa
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select * from t1 order by c;
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a b c d
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1 1 ab ab
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2 2 ac ac
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|
3 2 ad ad
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4 4 afe afe
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8 9 fff fff
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|
11 11 kkk kkk
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|
13 13 yyy aaa
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select * from t1 order by d;
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a b c d
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13 13 yyy aaa
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1 1 ab ab
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|
2 2 ac ac
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3 2 ad ad
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|
4 4 afe afe
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|
8 9 fff fff
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|
11 11 kkk kkk
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|
explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL b 16 NULL 7
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explain select * from t1 order by c;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL c 34 NULL 7
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explain select * from t1 order by d;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 7 Using filesort
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show create table t1;
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|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
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PRIMARY KEY (`a`),
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UNIQUE KEY `b` (`b`,`c`),
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UNIQUE KEY `c` (`c`,`d`),
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KEY `b_2` (`b`,`c`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1
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drop table t1;
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create table t1(a int not null, b int not null, c int, primary key (a), key (b)) engine = innodb;
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create table t3(a int not null, c int not null, d int, primary key (a), key (c)) engine = innodb;
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create table t4(a int not null, d int not null, e int, primary key (a), key (d)) engine = innodb;
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create table t2(a int not null, b int not null, c int not null, d int not null, e int,
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foreign key (b) references t1(b) on delete cascade,
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foreign key (c) references t3(c), foreign key (d) references t4(d))
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engine = innodb;
|
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alter table t1 drop index b;
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ERROR HY000: Cannot drop index 'b': needed in a foreign key constraint
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alter table t3 drop index c;
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ERROR HY000: Cannot drop index 'c': needed in a foreign key constraint
|
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alter table t4 drop index d;
|
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ERROR HY000: Cannot drop index 'd': needed in a foreign key constraint
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alter table t2 drop index b;
|
|
ERROR HY000: Cannot drop index 'b': needed in a foreign key constraint
|
|
alter table t2 drop index b, drop index c, drop index d;
|
|
ERROR HY000: Cannot drop index 'b': needed in a foreign key constraint
|
|
create unique index dc on t2 (d,c);
|
|
create index dc on t1 (b,c);
|
|
alter table t2 add primary key (a);
|
|
insert into t1 values (1,1,1);
|
|
insert into t3 values (1,1,1);
|
|
insert into t4 values (1,1,1);
|
|
insert into t2 values (1,1,1,1,1);
|
|
commit;
|
|
alter table t4 add constraint dc foreign key (a) references t1(a);
|
|
show create table t4;
|
|
Table Create Table
|
|
t4 CREATE TABLE `t4` (
|
|
`a` int(11) NOT NULL,
|
|
`d` int(11) NOT NULL,
|
|
`e` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `d` (`d`),
|
|
CONSTRAINT `dc` FOREIGN KEY (`a`) REFERENCES `t1` (`a`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
alter table t3 add constraint dc foreign key (a) references t1(a);
|
|
ERROR HY000: Can't create table '#sql-temporary' (errno: 121)
|
|
show create table t3;
|
|
Table Create Table
|
|
t3 CREATE TABLE `t3` (
|
|
`a` int(11) NOT NULL,
|
|
`c` int(11) NOT NULL,
|
|
`d` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `c` (`c`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
alter table t2 drop index b, add index (b);
|
|
show create table t2;
|
|
Table Create Table
|
|
t2 CREATE TABLE `t2` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) NOT NULL,
|
|
`c` int(11) NOT NULL,
|
|
`d` int(11) NOT NULL,
|
|
`e` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
UNIQUE KEY `dc` (`d`,`c`),
|
|
KEY `c` (`c`),
|
|
KEY `b` (`b`),
|
|
CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`b`) REFERENCES `t1` (`b`) ON DELETE CASCADE,
|
|
CONSTRAINT `t2_ibfk_2` FOREIGN KEY (`c`) REFERENCES `t3` (`c`),
|
|
CONSTRAINT `t2_ibfk_3` FOREIGN KEY (`d`) REFERENCES `t4` (`d`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
delete from t1;
|
|
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t4`, CONSTRAINT `dc` FOREIGN KEY (`a`) REFERENCES `t1` (`a`))
|
|
drop index dc on t4;
|
|
ERROR 42000: Can't DROP 'dc'; check that column/key exists
|
|
alter table t3 drop foreign key dc;
|
|
ERROR HY000: Error on rename of './test/t3' to '#sql2-temporary' (errno: 152)
|
|
alter table t4 drop foreign key dc;
|
|
select * from t2;
|
|
a b c d e
|
|
1 1 1 1 1
|
|
delete from t1;
|
|
select * from t2;
|
|
a b c d e
|
|
drop table t2,t4,t3,t1;
|
|
create table t1(a int not null, b int, c char(10), d varchar(20), primary key (a))
|
|
engine = innodb default charset=utf8;
|
|
insert into t1 values (1,1,'ab','ab'),(2,2,'ac','ac'),(3,2,'ad','ad'),(4,4,'afe','afe');
|
|
commit;
|
|
alter table t1 add unique index (b);
|
|
ERROR 23000: Duplicate entry '2' for key 'b'
|
|
insert into t1 values(8,9,'fff','fff');
|
|
select * from t1;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by b;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by c;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by d;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
|
|
explain select * from t1 order by d;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=utf8
|
|
alter table t1 add index (b);
|
|
insert into t1 values(10,10,'kkk','iii');
|
|
select * from t1;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
select * from t1 order by b;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
select * from t1 order by c;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
select * from t1 order by d;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL b 5 NULL 6
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
|
|
explain select * from t1 order by d;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 6 Using filesort
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `b` (`b`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=utf8
|
|
alter table t1 add unique index (c), add index (d);
|
|
insert into t1 values(11,11,'aaa','mmm');
|
|
select * from t1;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
11 11 aaa mmm
|
|
select * from t1 order by b;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
11 11 aaa mmm
|
|
select * from t1 order by c;
|
|
a b c d
|
|
11 11 aaa mmm
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
select * from t1 order by d;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 kkk iii
|
|
11 11 aaa mmm
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL b 5 NULL 7
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL c 31 NULL 7
|
|
explain select * from t1 order by d;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL d 63 NULL 7
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
UNIQUE KEY `c` (`c`),
|
|
KEY `b` (`b`),
|
|
KEY `d` (`d`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=utf8
|
|
check table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 check status OK
|
|
drop table t1;
|
|
create table t1(a int not null, b int, c char(10), d varchar(20), primary key (a))
|
|
engine = innodb default charset=ucs2;
|
|
insert into t1 values (1,1,'ab','ab'),(2,2,'ac','ac'),(3,2,'ad','ad'),(4,4,'afe','afe');
|
|
commit;
|
|
alter table t1 add unique index (b);
|
|
ERROR 23000: Duplicate entry '2' for key 'b'
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=ucs2
|
|
alter table t1 add index (b);
|
|
insert into t1 values(8,9,'fff','fff');
|
|
select * from t1;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by b;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by c;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by d;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL b 5 NULL 5
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
|
|
explain select * from t1 order by d;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 5 Using filesort
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `b` (`b`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=ucs2
|
|
alter table t1 add unique index (c), add index (d);
|
|
insert into t1 values(10,10,'aaa','kkk');
|
|
select * from t1;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 aaa kkk
|
|
select * from t1 order by b;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 aaa kkk
|
|
select * from t1 order by c;
|
|
a b c d
|
|
10 10 aaa kkk
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
select * from t1 order by d;
|
|
a b c d
|
|
1 1 ab ab
|
|
2 2 ac ac
|
|
3 2 ad ad
|
|
4 4 afe afe
|
|
8 9 fff fff
|
|
10 10 aaa kkk
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL b 5 NULL 6
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL c 21 NULL 6
|
|
explain select * from t1 order by d;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL d 43 NULL 6
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
UNIQUE KEY `c` (`c`),
|
|
KEY `b` (`b`),
|
|
KEY `d` (`d`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=ucs2
|
|
check table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 check status OK
|
|
drop table t1;
|
|
create table t1(a int not null, b int) engine = innodb;
|
|
insert into t1 values (1,1),(1,1),(1,1),(1,1);
|
|
alter table t1 add unique index (a);
|
|
ERROR 23000: Duplicate entry '1' for key 'a'
|
|
alter table t1 add unique index (b);
|
|
ERROR 23000: Duplicate entry '1' for key 'b'
|
|
alter table t1 add unique index (a), add unique index(b);
|
|
ERROR 23000: Duplicate entry '1' for key 'a'
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
drop table t1;
|
|
create table t1(a int not null, c int not null,b int, primary key(a), unique key(c), key(b)) engine = innodb;
|
|
alter table t1 drop index c, drop index b;
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`c` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
drop table t1;
|
|
create table t1(a int not null, b int, primary key(a)) engine = innodb;
|
|
alter table t1 add index (b);
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `b` (`b`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
drop table t1;
|
|
create table t1(a int not null, b int, c char(10), d varchar(20), primary key (a)) engine = innodb;
|
|
insert into t1 values (1,1,'ab','ab'),(2,2,'ac','ac'),(3,3,'ac','ac'),(4,4,'afe','afe');
|
|
alter table t1 add unique index (b), add unique index (c), add unique index (d);
|
|
ERROR 23000: Duplicate entry 'ac' for key 'c'
|
|
alter table t1 add unique index (b), add index (d), add unique index (c);
|
|
ERROR 23000: Duplicate entry 'ac' for key 'c'
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) DEFAULT NULL,
|
|
`c` char(10) DEFAULT NULL,
|
|
`d` varchar(20) DEFAULT NULL,
|
|
PRIMARY KEY (`a`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
drop table t1;
|
|
create table t1(a int not null, b int not null, c int, primary key (a), key(c)) engine=innodb;
|
|
insert into t1 values (5,1,5),(4,2,4),(3,3,3),(2,4,2),(1,5,1);
|
|
alter table t1 add unique index (b);
|
|
insert into t1 values (10,20,20),(11,19,19),(12,18,18),(13,17,17);
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) NOT NULL,
|
|
`c` int(11) DEFAULT NULL,
|
|
PRIMARY KEY (`a`),
|
|
UNIQUE KEY `b` (`b`),
|
|
KEY `c` (`c`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
check table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 check status OK
|
|
explain select * from t1 order by c;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL c 5 NULL 9
|
|
explain select * from t1 order by a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL PRIMARY 4 NULL 9
|
|
explain select * from t1 order by b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL b 4 NULL 9
|
|
select * from t1 order by a;
|
|
a b c
|
|
1 5 1
|
|
2 4 2
|
|
3 3 3
|
|
4 2 4
|
|
5 1 5
|
|
10 20 20
|
|
11 19 19
|
|
12 18 18
|
|
13 17 17
|
|
select * from t1 order by b;
|
|
a b c
|
|
5 1 5
|
|
4 2 4
|
|
3 3 3
|
|
2 4 2
|
|
1 5 1
|
|
13 17 17
|
|
12 18 18
|
|
11 19 19
|
|
10 20 20
|
|
select * from t1 order by c;
|
|
a b c
|
|
1 5 1
|
|
2 4 2
|
|
3 3 3
|
|
4 2 4
|
|
5 1 5
|
|
13 17 17
|
|
12 18 18
|
|
11 19 19
|
|
10 20 20
|
|
drop table t1;
|
|
create table t1(a int not null, b int not null) engine=innodb;
|
|
insert into t1 values (1,1);
|
|
alter table t1 add primary key(b);
|
|
insert into t1 values (2,2);
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL,
|
|
`b` int(11) NOT NULL,
|
|
PRIMARY KEY (`b`)
|
|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
|
|
check table t1;
|
|
Table Op Msg_type Msg_text
|
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test.t1 check status OK
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select * from t1;
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a b
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1 1
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2 2
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explain select * from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2
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explain select * from t1 order by a;
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|
id select_type table type possible_keys key key_len ref rows Extra
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|
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using filesort
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explain select * from t1 order by b;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL PRIMARY 4 NULL 2
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|
checksum table t1;
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Table Checksum
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|
test.t1 582702641
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drop table t1;
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create table t1(a int not null) engine=innodb;
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insert into t1 values (1);
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alter table t1 add primary key(a);
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insert into t1 values (2);
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show create table t1;
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|
Table Create Table
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|
t1 CREATE TABLE `t1` (
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`a` int(11) NOT NULL,
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PRIMARY KEY (`a`)
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|
) ENGINE=InnoDB DEFAULT CHARSET=latin1
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|
check table t1;
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|
Table Op Msg_type Msg_text
|
|
test.t1 check status OK
|
|
commit;
|
|
select * from t1;
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|
a
|
|
1
|
|
2
|
|
explain select * from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL PRIMARY 4 NULL 2 Using index
|
|
explain select * from t1 order by a;
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|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index NULL PRIMARY 4 NULL 2 Using index
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|
drop table t1;
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|
create table t1(a int, b blob, c text, d text not null) engine=innodb default charset = utf8;
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insert into t1 values (22,repeat('jejdkrun87',220),repeat('jejdkrun87',440),'jejdkrun87');
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|
insert into t1 values (44,repeat('adfd72nh9k',440),repeat('adfd72nh9k',880),'adfd72nh9k');
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|
insert into t1 values (null,null,null,'null');
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|
select count(*) from t1 where a=44;
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|
count(*)
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|
1
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|
select a,b=repeat(d,10*a),c=repeat(d,20*a) from t1;
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|
a b=repeat(d,10*a) c=repeat(d,20*a)
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|
22 1 1
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|
44 1 1
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|
NULL NULL NULL
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|
select a,length(b),length(c),d from t1;
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|
a length(b) length(c) d
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|
22 2200 4400 jejdkrun87
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|
44 4400 8800 adfd72nh9k
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|
NULL NULL NULL null
|
|
alter table t1 add primary key (a), add key (b(20));
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|
ERROR 42000: All parts of a PRIMARY KEY must be NOT NULL; if you need NULL in a key, use UNIQUE instead
|
|
delete from t1 where d='null';
|
|
alter table t1 add primary key (a), add key (b(20));
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|
select count(*) from t1 where a=44;
|
|
count(*)
|
|
1
|
|
select a,b=repeat(d,10*a),c=repeat(d,20*a) from t1;
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|
a b=repeat(d,10*a) c=repeat(d,20*a)
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|
22 1 1
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|
44 1 1
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|
select a,length(b),length(c),d from t1;
|
|
a length(b) length(c) d
|
|
22 2200 4400 jejdkrun87
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|
44 4400 8800 adfd72nh9k
|
|
insert into t1 values (33,repeat('adfdpplkeock',330),repeat('adfdpplkeock',660),'adfdpplkeock');
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|
insert into t1 values (55,repeat('adfdijnmnb78k',550),repeat('adfdijnmnb78k',1100),'adfdijnmnb78k');
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|
insert into t1 values (66,repeat('adfdijn0loKNHJik',660),repeat('adfdijn0loKNHJik',1320),'adfdijn0loKNHJik');
|
|
show create table t1;
|
|
Table Create Table
|
|
t1 CREATE TABLE `t1` (
|
|
`a` int(11) NOT NULL DEFAULT '0',
|
|
`b` blob,
|
|
`c` text,
|
|
`d` text NOT NULL,
|
|
PRIMARY KEY (`a`),
|
|
KEY `b` (`b`(20))
|
|
) ENGINE=InnoDB DEFAULT CHARSET=utf8
|
|
check table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 check status OK
|
|
explain select * from t1 where b like 'adfd%';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range b b 23 NULL 2 Using where
|
|
select a,b=repeat(d,10*a),c=repeat(d,20*a) from t1;
|
|
a b=repeat(d,10*a) c=repeat(d,20*a)
|
|
22 1 1
|
|
33 1 1
|
|
44 1 1
|
|
55 1 1
|
|
66 1 1
|
|
select a,length(b),length(c),d from t1;
|
|
a length(b) length(c) d
|
|
22 2200 4400 jejdkrun87
|
|
33 3960 7920 adfdpplkeock
|
|
44 4400 8800 adfd72nh9k
|
|
55 7150 14300 adfdijnmnb78k
|
|
66 10560 21120 adfdijn0loKNHJik
|
|
drop table t1;
|