mysql 中sum (if()) 和 sum()

1、sum (if())

将表tb_out_people中的数据根据out_peo_id、pro_id、type进行归并，计算其对应overtime的和。

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SELECT out_peo_id,pro_id,sum(if(type='0',overtime,0 )) as "0",
sum(if(type='1',overtime,0 )) as "1",sum(if(type='2',overtime,0 )) as "2"
FROM tb_out_people
GROUP BY out_peo_id,pro_id

得到的结果为：

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2、简单sum()

select out_peo_id,SUM(overtime) as "加班时长"
from temp_test 
group by out_peo_id