sql - 使用count优化SQL查询

Question

我使用 ASP.NET 成员(member)资格，除此之外，我还添加了一些与用户具有一对多关系的表。

一个用户拥有多支笔、笔记本等。

我正在编写一个自定义成员(member)资格提供程序，并修改了选择查询以检索有关用户的所有信息以及用户拥有的笔数量和“工具”总数，但该查询显然执行灾难性的操作。 有办法获取这些信息吗？ 这是我尝试过的:

SET STATISTICS TIME ON
SELECT  m.Email, m.PasswordQuestion, m.IsApproved, m.CreateDate, m.LastLoginDate,
        u.LastActivityDate, m.LastPasswordChangedDate, u.UserId, m.IsLockedOut, 
        m.LastLockoutDate, CAST(m.Comment as nvarchar(max)) as Comment, 
        COUNT(DISTINCT cl.Id) AS NumberOfPens, 
        COUNT(DISTINCT cf.Id)+
             COUNT(DISTINCT cm.Id) +
             COUNT(DISTINCT ce.Id) +
             COUNT(DISTINCT cl.Id) +
             COUNT(DISTINCT cp.Id) +
             COUNT(DISTINCT csl.Id)+
             COUNT(DISTINCT cs.Id) +
             COUNT(DISTINCT cshl.Id) AS NumberOfTools
FROM  aspnet_Membership AS m 
      INNER JOIN aspnet_Users AS u ON m.UserId = u.UserId 
      INNER JOIN Pens AS cf ON u.UserId = cf.Owner 
      INNER JOIN Notebooks AS cm ON u.UserId = cm.Owner 
      INNER JOIN Rulers AS ce ON u.UserId = ce.Owner 
      INNER JOIN Calculators AS cl ON u.UserId = cl.Owner 
      CROSS JOIN aspnet_Applications AS a
GROUP BY u.UserId, m.Email, m.PasswordQuestion, m.IsApproved, 
         m.CreateDate, m.LastLoginDate, u.LastActivityDate, 
         m.LastPasswordChangedDate, m.IsLockedOut, m.LastLockoutDate, 
         CAST(m.Comment as nvarchar(max))

SET STATISTICS TIME OFF

9 分 11 秒，91 位用户!

Answer 1

SELECT  m.Email, m.PasswordQuestion, m.IsApproved, m.CreateDate, m.LastLoginDate,
        u.LastActivityDate, m.LastPasswordChangedDate, u.UserId, m.IsLockedOut, 
        m.LastLockoutDate, CAST(m.Comment as nvarchar(max)) as Comment,
        penCount,
        notebookCount + rulerCount + calculatorCount AS toolCount
FROM    aspnet_Membership m
JOIN    aspnet_Users u
ON      u.userId = m.userId
CROSS APPLY
        (
        SELECT  COUNT(*)
        FROM    pens
        WHERE   owner = u.UserId
        ) p (penCount)
CROSS APPLY
        (
        SELECT  COUNT(*)
        FROM    notebooks
        WHERE   owner = u.UserId
        ) n (notebookCount)
CROSS APPLY
        (
        SELECT  COUNT(*)
        FROM    rulers
        WHERE   owner = u.UserId
        ) r (rulerCount)
CROSS APPLY
        (
        SELECT  COUNT(*)
        FROM    calculators
        WHERE   owner = u.UserId
        ) c (calculatorCount)