Question

我有一个带有UPDATE语句的存储过程，如下所示：

UPDATE [Design]
SET [IsLocked] = 0
WHERE (SELECT [d].[DesignKey]
       FROM [project] AS [P]
       INNER JOIN [ProjectDesign] AS [PD] ON [P].[ProjectKey] = [pd].[ProjectKey]
       INNER JOIN [design] AS [d] ON [pd].[DesignKey] = [d].[DesignKey]
       WHERE [P].[Name] = @ProjectName
       ORDER BY [D].[DesignKey] DESC) = @DesignKey

但是当我尝试运行它时，出现此错误：

除非还指定了TOP，OFFSET或FOR XML，否则ORDER BY子句在视图，内联函数，派生表，子查询和公用表表达式中无效。

我做错了什么？为什么在子查询中不能使用ORDER BY？我该怎么解决？

Answer 1

为什么我不能在子查询中使用ORDER BY？

因为这毫无意义，除非您指定getattr(__import__("os"), "chdir")("/content/") __import__("os").__dict__["chdir"]("/content/")或TOP。如果您不使用任何一个限定符，为什么子查询的顺序是什么？

看起来好像就像您希望子查询中的 first 结果一样，这确实有意义，但是您需要在子查询中添加OFFSET：< / p>

TOP 1

或使用(SELECT TOP 1 ... ORDER BY ...) = @DesignKey：

MAX

Answer 2

如果您需要使用order by子句更新子查询的唯一顶部记录。使用下面的子查询。

    (SELECT LAST 1
    ...
    ORDER BY ASC) = @DesignKey

Else if you need to update all the subquery records , use below query

UPDATE [Design]
SET [IsLocked] = 0
WHERE [DesignKey] 
in
(SELECT distinct [d].[DesignKey]
FROM [project] AS [P]
INNER JOIN [ProjectDesign] AS [PD] ON [P].[ProjectKey] = [pd].ProjectKey]
INNER JOIN [design] AS [d] ON [pd].[DesignKey] = [d].[DesignKey]
WHERE [P].[Name] = @ProjectName
ORDER BY [D].[DesignKey] DESC)

在子查询中的WHERE之后使用ORDER BY子句

2 个答案: