SQL WHERE用于具有GROUP BY的SELECT语句中的COUNT

Question

SELECT COUNT(pkNotification) AS caseTotal
,COUNT(fkCaseType) AS Suspected
, COUNT(fkCaseType) AS Confirmed
, Disease.Name 
FROM [Notification] 
INNER JOIN [Disease] ON Notification.fkDisease=Disease.pkDisease 
GROUP BY Disease.Name

这是我的发言.但是我需要COUNT(fkCaseType)AS被怀疑只有当fkCaseType = 1时才被怀疑,而确认为fkcaseType = 2时.

问题是我做了子查询的地方,我遇到了问题.

Answer 1

COUNT(CASE WHEN fkCaseType = 1 THEN 1 END) Suspected,
COUNT(CASE WHEN fkCaseType = 2 THEN 1 END) Confirmed

在第一个语句中fkCaseType = 1- 然后返回1因此计数COUNT,NULL否则,跳过.对于第二个 - 相同.