为sql中的某些记录返回零

Question

我在存储过程中有一个查询来计算表中的一些记录：

SELECT
  t_Supporter.supporterID,
  COUNT(t_ticket.ticketID) AS totalTicket
FROM t_Supporter
INNER JOIN t_ticket
  ON t_Supporter.supporterID = t_ticket.supporterID_FK
WHERE (t_Supporter.orgSectionID_FK = @orgID)
GROUP BY t_Supporter.supporterID

如果t_Supporter.supporterID中t_ticket没有记录，如何让我的查询返回零。

Answer 1

您需要使用条件汇总将COUNT更改为SUM，将INNER JOIN更改为LEFT OUTER

SELECT t_Supporter.supporterID, SUM(CASE WHEN t_ticket.ticketID IS NOT NULL THEN 1 ELSE 0 END) AS totalTicket
FROM t_Supporter LEFT OUTER JOIN
     t_ticket ON t_Supporter.supporterID = t_ticket.supporterID_FK
WHERE  (t_Supporter.orgSectionID_FK = @orgID)
GROUP BY t_Supporter.supporterID