SELECT COUNT外连接和WHERE

Question

我有以下SQL：

SELECT 
    ud.firstname + ' ' + ud.lastname, 
    COUNT(a.createdDate) AS ActivityCount, 
    au.LastActivityDate 
FROM 
    dbo.aspnet_Users au 
    INNER JOIN dbo.UserDetails ud 
    ON au.UserId = ud.AspNetUserId 
    LEFT OUTER JOIN dbo.audit a 
    ON au.LoweredUserName = a.username 
WHERE 
    (
     au.LoweredUserName IN ('u1', 'u2', 'u3') 
    ) 
AND a.createdDate > '2012-09-18' 
GROUP BY ud.firstname + ' ' + ud.lastname, au.LastActivityDate 
ORDER BY au.LastActivityDate DESC 

但是，让我们说，u1和u3没有任何活性，因为该2012-09-18 - 那么结果只包含u2。

我以为LEFT OUTER JOIN确信，我得到的所有记录aspnet_Users - 但我想这是因为我WHERE条款秒条件过滤另一个表...

什么我需要改变为了让所有指定的用户，然后一零ActivityCount是否存在在预定期间没有数据？

Answer 1

，但我想这是由于在秒条件下我的WHERE子句过滤另一个表...

右键，在WHERE子句createdDate的条件从dbo.audit抑制记录。你可以将其移至LEFT OUTER JOIN条件列表来得到想要的结果。

Answer 2

SELECT 
    ud.firstname + ' ' + ud.lastname, 
    sum(case when a.createdDate is null then 0 else 1 end) AS ActivityCount, 
    au.LastActivityDate 
FROM 
    dbo.aspnet_Users au 
    INNER JOIN dbo.UserDetails ud 
    ON au.UserId = ud.AspNetUserId 
    LEFT OUTER JOIN dbo.audit a 
    ON au.LoweredUserName = a.username 
WHERE 
    (au.LoweredUserName IN ('u1', 'u2', 'u3')) 
AND (a.createdDate > '2012-09-18' or a.createdDate is null) 
GROUP BY 
    ud.firstname + ' ' + ud.lastname, 
    au.LastActivityDate 
ORDER BY au.LastActivityDate DESC