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			97 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			97 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
drop table if exists t1;
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SET SQL_SAFE_UPDATES=1,SQL_SELECT_LIMIT=4, SQL_MAX_JOIN_SIZE=9;
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create table t1 (a int auto_increment primary key, b char(20));
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insert into t1 values(1,"test");
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SELECT SQL_BUFFER_RESULT * from t1;
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a	b
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1	test
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update t1 set b="a" where a=1;
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delete from t1 where a=1;
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insert into t1 values(1,"test"),(2,"test2");
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SELECT SQL_BUFFER_RESULT * from t1;
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a	b
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1	test
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2	test2
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update t1 set b="a" where a=1;
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select 1 from t1,t1 as t2,t1 as t3;
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1
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1
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1
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1
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1
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update t1 set b="a";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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update t1 set b="a" where b="test";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1;
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1 where b="test";
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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delete from t1 where a+0=1;
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ERROR HY000: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
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select 1 from t1,t1 as t2,t1 as t3,t1 as t4,t1 as t5;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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update t1 set b="a" limit 1;
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update t1 set b="a" where b="b" limit 2;
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delete from t1 where b="test" limit 1;
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delete from t1 where a+0=1 limit 2;
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alter table t1 add key b (b);
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SET MAX_JOIN_SIZE=2;
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SELECT @@MAX_JOIN_SIZE, @@SQL_BIG_SELECTS;
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@@MAX_JOIN_SIZE	@@SQL_BIG_SELECTS
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2	0
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insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a");
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SELECT * from t1 order by a;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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SET SQL_BIG_SELECTS=1;
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SELECT * from t1 order by a;
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a	b
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2	test2
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3	a
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4	a
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5	a
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SET MAX_JOIN_SIZE=2;
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SELECT * from t1;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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SET MAX_JOIN_SIZE=DEFAULT;
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SELECT * from t1;
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a	b
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2	test2
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3	a
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4	a
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5	a
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SELECT @@MAX_SEEKS_FOR_KEY;
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@@MAX_SEEKS_FOR_KEY
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4294967295
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analyze table t1;
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Table	Op	Msg_type	Msg_text
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test.t1	analyze	status	OK
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insert into t1 values (null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a"),(null,"a");
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.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	b	NULL	NULL	NULL	21	
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1	SIMPLE	t2	ref	b	b	21	test.t1.b	6	Using where
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set MAX_SEEKS_FOR_KEY=1;
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explain select STRAIGHT_JOIN * from t1,t1 as t2 where t1.b=t2.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	b	NULL	NULL	NULL	21	
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1	SIMPLE	t2	ref	b	b	21	test.t1.b	6	Using where
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SET MAX_SEEKS_FOR_KEY=DEFAULT;
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drop table t1;
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create table t1 (a int);
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insert into t1 values (1),(2),(3),(4),(5);
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insert into t1 select * from t1;
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insert into t1 select * from t1;
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insert into t1 select * from t1;
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set local  max_join_size=8;
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select * from (select * from t1) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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set local  max_join_size=1;
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select * from (select * from t1 a, t1 b) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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set local  max_join_size=1;
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select * from (select 1 union select 2 union select 3) x;
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ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay
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drop table t1;
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SET SQL_SAFE_UPDATES=0,SQL_SELECT_LIMIT=DEFAULT, SQL_MAX_JOIN_SIZE=DEFAULT;
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