Question

我正在使用mysql，必须在不同的三种情况下从db表中归档一个

my db table user_pay
fields- username,amt,postingDate,category

我想要类似的结果

username  amtbeforedate  amtbetweendate amtcategory
john            500           1000          1200

每个字段的条件

where conditions- startdate, enddate, category
username
amtbeforedate= sum(amt) From user_pay WHERE postingDate >  startdate
amtbetweendate=sum(amt) From user_pay WHERE postingDate BETWEEN startdate AND enddate AND (category='paid' OR category='notpaid')
amtcategory =sum(amt) From user_pay WHERE postingDate BETWEEN startdate AND enddate AND (category='adjustment')

我希望此结果在单个查询中。我尝试不同的示例，但没有任何结果查询只会被调用一次，而不是每行一次

Answer 1

如果我理解您提出的问题是正确的，您可以在总和内应用条件像这样的东西

SUM(CASE WHEN postingDate > startdate THEN amt ELSE 0 END) as amtbeforedate

整个查询都是这样

select 
 SUM(CASE WHEN postingDate > startdate THEN amt ELSE 0 END) as amtbeforedate
 SUM(CASE WHEN postingDate BETWEEN startdate AND enddate AND (category='paid' OR category='notpaid')
THEN amt ELSE 0 END) as amtbetweendate
 SUM(CASE WHEN postingDate BETWEEN startdate AND enddate AND (category='adjustment') THEN amt ELSE 0 END) as amtbeforedate
from user_pay

希望对您有帮助

MySQL选择一个具有不同条件的字段

1 个答案: