如何优化几个“WHERE (Select ....) = value”来自同一张桌子

发布于 2024-11-06 14:30:30 字数 433 浏览 1 评论 0原文

对我来说很难起一个主题名称。但我可以举一个例子：

WHERE   (SELECT [ID_Line] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2
AND     (SELECT [DataType] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2

在这里，当我确实需要类似的东西时，我正在处理 2 个查询：

WHERE   (SELECT [ID_Line],[DataType] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2,2

但是 SQL 不适用于元组，所以我必须在这里进行 Inner Join 吗？

原文

It's hard to compose a topic name for me. But I can show an example :

WHERE   (SELECT [ID_Line] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2
AND     (SELECT [DataType] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2

Here I'm processing 2 queries when I really need something like that :

WHERE   (SELECT [ID_Line],[DataType] FROM [Event] WHERE [Event].[Name]  = [A].[Col]) = 2,2

but SQL doesn't work with tuples, so must I make Inner Join here ?

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乖乖兔^ω^ 2024-11-13 14:30:30

您可以尝试这样的操作：

WHERE EXISTS (
    SELECT [ID_Line] FROM [Event] WHERE
        [Event].[Name]  = [A].[Col] AND
        [Event].[ID_Line] = 2 AND
        [Event].[DataType] = 2
)

如果您提供有关完整查询和数据库结构的更多信息，则可以给出更准确的答案。这可能不是最好的解决方案。

you can try something like this :

WHERE EXISTS (
    SELECT [ID_Line] FROM [Event] WHERE
        [Event].[Name]  = [A].[Col] AND
        [Event].[ID_Line] = 2 AND
        [Event].[DataType] = 2
)

If you provide more information about the complete query and your database structure, a more precise answer could be given. It is possible that this isn't the best solution.

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