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CREATE TABLE tb (
name VARCHAR ( 10 ),
course VARCHAR ( 10 ),
score INT
);
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insert into tb values('张三' , '语文' , 74);
insert into tb values('张三' , '数学' , 83);
insert into tb values('张三' , '物理' , 93);
insert into tb values('李四' , '语文' , 74);
insert into tb values('李四' , '数学' , 84);
insert into tb values('李四' , '物理' , 94);
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行->列
simple
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SELECT
name AS name,
max( CASE course WHEN '语文' THEN score ELSE 0 END ) 语文,
max( CASE course WHEN '数学' THEN score ELSE 0 END ) 数学,
max( CASE course WHEN '物理' THEN score ELSE 0 END ) 物理
FROM
tb
GROUP BY
name
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max( CASE course WHEN '语文' THEN score ELSE 0 END )
SUM(IF(course="语文",score,0))
CASE WHEN signal_type='macd_15_dea_up_0' and op_type='buy' THEN 1 WHEN signal_type='macd_15_dea_up_0' and op_type='sell' THEN -1 ELSE 0 END as macd_15_dea_up_0
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if expr1 then expr2 else expr3
if expr1 not NULL then expr1 else expr2
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CASE value WHEN [compare_value] THEN result [WHEN [compare_value] THEN result ...] [ELSE result] END
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