SQL选择COUNT(值=值)可能吗？

Question

我想计算所有只有我想要的值的行:

SELECT Users.Balance,
       Users.FreeBids,
       COUNT(Bids.Burned = 0) AS 'ActiveBids',
       COUNT(Bids.Burned = 1) AS 'BurnedBids'
FROM   Users
       INNER JOIN Bids
         ON Users.ID = Bids.BidderID
WHERE  Users.ID = 2
GROUP  BY Users.Balance,
          Users.FreeBids  

它说" Invalid Syntax Neat '='没有'='就可以完美地工作.我如何计算Burned = 1并且Burned = 0的行？

谢谢,丹

Answer 1

使用CASE声明

COUNT(CASE WHEN Bids.Burned=0 THEN 1 END) AS 'ActiveBids', 
COUNT(CASE WHEN Bids.Burned=1 THEN 1 END) AS 'BurnedBids'

有隐含的ELSE NULL.COUNT只计算NOT NULL值,这样就可以得到你需要的结果.