SQL SUM值满足2个条件

Question

我正在尝试创建一个计算每个月的信用卡和借记卡的查询.这些值在名为SUM的列中,每个记录都有一个字段,表示它是信用卡还是借记卡(ex_type).我已经设法得到所有字段的总和(虽然它也不正确 - 但我只是将所有值加起来,无论它是信用卡还是借记卡).

SELECT sum(sum) as total FROM acc where month='$month'

但我无法想办理信用卡和借记卡

所以,总结一下......我希望将以下两个查询合二为一.

1. Select sum(sum) as Debit from acc where ex_type='Debit' and month='$month'
2. Select sum(sum) as Credit from acc where ex_type='Credit' and month='$month'

所以,任何帮助都非常感谢.

Answer 1

试试吧 CASE

Select sum(CASE WHEN ex_type='Debit' THEN `sum` ELSE 0 END) as Debit,
sum(CASE WHEN ex_type='Credit' THEN `sum` ELSE 0 END) as Credit FROM ...