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699291a8e6
- Make the range-et-al optimizer produce E(#table records after table
condition is applied),
- Make the join optimizer use this value,
- Add "filtered" column to EXPLAIN EXTENDED to show
fraction of records left after table condition is applied
- Adjust test results, add comments
203 lines
8.8 KiB
Plaintext
203 lines
8.8 KiB
Plaintext
drop table if exists t1,t2;
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select CASE "b" when "a" then 1 when "b" then 2 END;
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CASE "b" when "a" then 1 when "b" then 2 END
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2
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select CASE "c" when "a" then 1 when "b" then 2 END;
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CASE "c" when "a" then 1 when "b" then 2 END
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NULL
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select CASE "c" when "a" then 1 when "b" then 2 ELSE 3 END;
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CASE "c" when "a" then 1 when "b" then 2 ELSE 3 END
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3
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select CASE BINARY "b" when "a" then 1 when "B" then 2 WHEN "b" then "ok" END;
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CASE BINARY "b" when "a" then 1 when "B" then 2 WHEN "b" then "ok" END
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ok
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select CASE "b" when "a" then 1 when binary "B" then 2 WHEN "b" then "ok" END;
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CASE "b" when "a" then 1 when binary "B" then 2 WHEN "b" then "ok" END
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ok
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select CASE concat("a","b") when concat("ab","") then "a" when "b" then "b" end;
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CASE concat("a","b") when concat("ab","") then "a" when "b" then "b" end
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a
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select CASE when 1=0 then "true" else "false" END;
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CASE when 1=0 then "true" else "false" END
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false
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select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
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CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END
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one
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explain extended select CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
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Warnings:
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Note 1003 select (case 1 when 1 then _latin1'one' when 2 then _latin1'two' else _latin1'more' end) AS `CASE 1 when 1 then "one" WHEN 2 then "two" ELSE "more" END`
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select CASE 2.0 when 1 then "one" WHEN 2.0 then "two" ELSE "more" END;
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CASE 2.0 when 1 then "one" WHEN 2.0 then "two" ELSE "more" END
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two
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select (CASE "two" when "one" then "1" WHEN "two" then "2" END) | 0;
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(CASE "two" when "one" then "1" WHEN "two" then "2" END) | 0
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2
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select (CASE "two" when "one" then 1.00 WHEN "two" then 2.00 END) +0.0;
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(CASE "two" when "one" then 1.00 WHEN "two" then 2.00 END) +0.0
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2.00
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select case 1/0 when "a" then "true" else "false" END;
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case 1/0 when "a" then "true" else "false" END
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false
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select case 1/0 when "a" then "true" END;
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case 1/0 when "a" then "true" END
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NULL
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select (case 1/0 when "a" then "true" END) | 0;
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(case 1/0 when "a" then "true" END) | 0
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NULL
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select (case 1/0 when "a" then "true" END) + 0.0;
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(case 1/0 when "a" then "true" END) + 0.0
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NULL
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select case when 1>0 then "TRUE" else "FALSE" END;
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case when 1>0 then "TRUE" else "FALSE" END
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TRUE
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select case when 1<0 then "TRUE" else "FALSE" END;
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case when 1<0 then "TRUE" else "FALSE" END
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FALSE
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create table t1 (a int);
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insert into t1 values(1),(2),(3),(4);
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select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
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fcase count(*)
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0 2
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2 1
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3 1
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explain extended select case a when 1 then 2 when 2 then 3 else 0 end as fcase, count(*) from t1 group by fcase;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 4 100.00 Using temporary; Using filesort
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Warnings:
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Note 1003 select (case `test`.`t1`.`a` when 1 then 2 when 2 then 3 else 0 end) AS `fcase`,count(0) AS `count(*)` from `test`.`t1` group by (case `test`.`t1`.`a` when 1 then 2 when 2 then 3 else 0 end)
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select case a when 1 then "one" when 2 then "two" else "nothing" end as fcase, count(*) from t1 group by fcase;
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fcase count(*)
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nothing 2
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one 1
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two 1
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drop table t1;
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create table t1 (row int not null, col int not null, val varchar(255) not null);
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insert into t1 values (1,1,'orange'),(1,2,'large'),(2,1,'yellow'),(2,2,'medium'),(3,1,'green'),(3,2,'small');
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select max(case col when 1 then val else null end) as color from t1 group by row;
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color
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orange
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yellow
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green
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drop table t1;
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SET NAMES latin1;
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CREATE TABLE t1 SELECT
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CASE WHEN 1 THEN _latin1'a' COLLATE latin1_danish_ci ELSE _latin1'a' END AS c1,
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CASE WHEN 1 THEN _latin1'a' ELSE _latin1'a' COLLATE latin1_danish_ci END AS c2,
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CASE WHEN 1 THEN 'a' ELSE 1 END AS c3,
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CASE WHEN 1 THEN 1 ELSE 'a' END AS c4,
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CASE WHEN 1 THEN 'a' ELSE 1.0 END AS c5,
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CASE WHEN 1 THEN 1.0 ELSE 'a' END AS c6,
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CASE WHEN 1 THEN 1 ELSE 1.0 END AS c7,
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CASE WHEN 1 THEN 1.0 ELSE 1 END AS c8,
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CASE WHEN 1 THEN 1.0 END AS c9,
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CASE WHEN 1 THEN 0.1e1 else 0.1 END AS c10,
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CASE WHEN 1 THEN 0.1e1 else 1 END AS c11,
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CASE WHEN 1 THEN 0.1e1 else '1' END AS c12
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;
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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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`c1` varchar(1) CHARACTER SET latin1 COLLATE latin1_danish_ci NOT NULL DEFAULT '',
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`c2` varchar(1) CHARACTER SET latin1 COLLATE latin1_danish_ci NOT NULL DEFAULT '',
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`c3` varbinary(1) NOT NULL DEFAULT '',
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`c4` varbinary(1) NOT NULL DEFAULT '',
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`c5` varbinary(4) NOT NULL DEFAULT '',
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`c6` varbinary(4) NOT NULL DEFAULT '',
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`c7` decimal(2,1) NOT NULL DEFAULT '0.0',
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`c8` decimal(2,1) NOT NULL DEFAULT '0.0',
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`c9` decimal(2,1) DEFAULT NULL,
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`c10` double NOT NULL DEFAULT '0',
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`c11` double NOT NULL DEFAULT '0',
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`c12` varbinary(5) NOT NULL DEFAULT ''
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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DROP TABLE t1;
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SELECT CASE
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WHEN 1
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THEN _latin1'a' COLLATE latin1_danish_ci
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ELSE _latin1'a' COLLATE latin1_swedish_ci
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END;
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ERROR HY000: Illegal mix of collations (latin1_danish_ci,EXPLICIT) and (latin1_swedish_ci,EXPLICIT) for operation 'case'
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SELECT CASE _latin1'a' COLLATE latin1_general_ci
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WHEN _latin1'a' COLLATE latin1_danish_ci THEN 1
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WHEN _latin1'a' COLLATE latin1_swedish_ci THEN 2
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END;
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ERROR HY000: Illegal mix of collations (latin1_general_ci,EXPLICIT), (latin1_danish_ci,EXPLICIT), (latin1_swedish_ci,EXPLICIT) for operation 'case'
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SELECT
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CASE _latin1'a' COLLATE latin1_general_ci WHEN _latin1'A' THEN '1' ELSE 2 END,
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CASE _latin1'a' COLLATE latin1_bin WHEN _latin1'A' THEN '1' ELSE 2 END,
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CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_swedish_ci THEN '1' ELSE 2 END,
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CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_bin THEN '1' ELSE 2 END
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;
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CASE _latin1'a' COLLATE latin1_general_ci WHEN _latin1'A' THEN '1' ELSE 2 END CASE _latin1'a' COLLATE latin1_bin WHEN _latin1'A' THEN '1' ELSE 2 END CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_swedish_ci THEN '1' ELSE 2 END CASE _latin1'a' WHEN _latin1'A' COLLATE latin1_bin THEN '1' ELSE 2 END
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1 2 1 2
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CREATE TABLE t1 SELECT COALESCE(_latin1'a',_latin2'a');
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ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation 'coalesce'
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CREATE TABLE t1 SELECT COALESCE('a' COLLATE latin1_swedish_ci,'b' COLLATE latin1_bin);
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ERROR HY000: Illegal mix of collations (latin1_swedish_ci,EXPLICIT) and (latin1_bin,EXPLICIT) for operation 'coalesce'
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CREATE TABLE t1 SELECT
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COALESCE(1), COALESCE(1.0),COALESCE('a'),
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COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
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COALESCE('a' COLLATE latin1_bin,'b');
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explain extended SELECT
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COALESCE(1), COALESCE(1.0),COALESCE('a'),
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COALESCE(1,1.0), COALESCE(1,'1'),COALESCE(1.1,'1'),
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COALESCE('a' COLLATE latin1_bin,'b');
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No tables used
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Warnings:
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Note 1003 select coalesce(1) AS `COALESCE(1)`,coalesce(1.0) AS `COALESCE(1.0)`,coalesce(_latin1'a') AS `COALESCE('a')`,coalesce(1,1.0) AS `COALESCE(1,1.0)`,coalesce(1,_latin1'1') AS `COALESCE(1,'1')`,coalesce(1.1,_latin1'1') AS `COALESCE(1.1,'1')`,coalesce((_latin1'a' collate latin1_bin),_latin1'b') AS `COALESCE('a' COLLATE latin1_bin,'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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`COALESCE(1)` int(1) NOT NULL DEFAULT '0',
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`COALESCE(1.0)` decimal(2,1) NOT NULL DEFAULT '0.0',
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`COALESCE('a')` varchar(1) NOT NULL DEFAULT '',
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`COALESCE(1,1.0)` decimal(2,1) NOT NULL DEFAULT '0.0',
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`COALESCE(1,'1')` varbinary(1) NOT NULL DEFAULT '',
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`COALESCE(1.1,'1')` varbinary(4) NOT NULL DEFAULT '',
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`COALESCE('a' COLLATE latin1_bin,'b')` varchar(1) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT ''
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) ENGINE=MyISAM DEFAULT CHARSET=latin1
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DROP TABLE t1;
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SELECT 'case+union+test'
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UNION
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SELECT CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END;
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case+union+test
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case+union+test
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nobug
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SELECT CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END;
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CASE LOWER('1') WHEN LOWER('2') THEN 'BUG' ELSE 'nobug' END
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nobug
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SELECT 'case+union+test'
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UNION
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SELECT CASE '1' WHEN '2' THEN 'BUG' ELSE 'nobug' END;
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case+union+test
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case+union+test
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nobug
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create table t1(a float, b int default 3);
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insert into t1 (a) values (2), (11), (8);
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select min(a), min(case when 1=1 then a else NULL end),
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min(case when 1!=1 then NULL else a end)
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from t1 where b=3 group by b;
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min(a) min(case when 1=1 then a else NULL end) min(case when 1!=1 then NULL else a end)
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2 2 2
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drop table t1;
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CREATE TABLE t1 (EMPNUM INT);
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INSERT INTO t1 VALUES (0), (2);
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CREATE TABLE t2 (EMPNUM DECIMAL (4, 2));
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INSERT INTO t2 VALUES (0.0), (9.0);
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SELECT COALESCE(t2.EMPNUM,t1.EMPNUM) AS CEMPNUM,
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t1.EMPNUM AS EMPMUM1, t2.EMPNUM AS EMPNUM2
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FROM t1 LEFT JOIN t2 ON t1.EMPNUM=t2.EMPNUM;
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CEMPNUM EMPMUM1 EMPNUM2
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0.00 0 0.00
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2.00 2 NULL
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SELECT IFNULL(t2.EMPNUM,t1.EMPNUM) AS CEMPNUM,
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t1.EMPNUM AS EMPMUM1, t2.EMPNUM AS EMPNUM2
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FROM t1 LEFT JOIN t2 ON t1.EMPNUM=t2.EMPNUM;
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CEMPNUM EMPMUM1 EMPNUM2
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0.00 0 0.00
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2.00 2 NULL
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DROP TABLE t1,t2;
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