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我是 SQL 的新手，因为我通常可以在不深入研究的情况下完成简单的查询/迁移，但是我有一个不涉及连接的更复杂的查询/迁移，我想知道当没有外部约束时如何删除在级联上使用。这是我的查询。我无法从谷歌搜索中找到一个好的答案。

WITH aDeleteVariable AS (SELECT TOP 1 FooID as id FROM [BSystem].[Foo].[bar] order by      
CreateTimeUTC desc)
DELETE FROM [BSystem].[Foo].[fooBar] where FooID = id
DELETE FROM [BSystem].[Foo].[bar] where FooID = id

所以我需要先删除 [BSystem].[Foo].fooBar，然后是 [BSystem].[Foo].[bar] 这将在运行时执行，因此不能硬编码。“1”真的会是n，但是我已经解决了那个代码。

尝试执行此查询时，我得到无效的列名“id” 。我该如何解决？

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1 回答 1

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您的DELETE陈述不引用aDeleteVariable. 该id列仅存在于 的上下文中aDeleteVariable。

你需要加入aDeleteVariable你的DELETE陈述。此外，您不能重用公用表表达式，因此您必须复制它。

请参阅此SQL Fiddle（带有简化的架构/表名称），但以下是您想要的。

WITH aDeleteVariable AS (SELECT TOP 1 FooID as id
        FROM [BSystem].[Foo].[bar] order by CreateTimeUTC desc)
DELETE FB 
        FROM [BSystem].[Foo].[fooBar] AS FB
        INNER JOIN aDeleteVariable AS DV ON (FB.FooID = DV.id);
WITH aDeleteVariable AS (SELECT TOP 1 FooID as id
        FROM [BSystem].[Foo].[bar] order by CreateTimeUTC desc)
DELETE B
        FROM [BSystem].[Foo].[bar] AS B
        INNER JOIN aDeleteVariable AS DV ON (B.FooID = DV.id);

当然，加入 to 后aDeleteVariable，您不需要id别名。以下将起作用。

WITH aDeleteVariable AS (SELECT TOP 1 FooID
        FROM [BSystem].[Foo].[bar] order by CreateTimeUTC desc)
DELETE FB 
        FROM [BSystem].[Foo].[fooBar] AS FB
        INNER JOIN aDeleteVariable AS DV ON (FB.FooID = DV.FooID);
WITH aDeleteVariable AS (SELECT TOP 1 FooID
        FROM [BSystem].[Foo].[bar] order by CreateTimeUTC desc)
DELETE B
        FROM [BSystem].[Foo].[bar] AS B
        INNER JOIN aDeleteVariable AS DV ON (B.FooID = DV.FooID);

鉴于有两个单独的公用表表达式，存在竞争条件，并且第二个表达式可能返回不同的FooID（或者当您将其适应N记录时返回多个）。您可能希望将 ID 选择到表变量中，而不是使用公用表表达式。以下应该工作。

DECLARE @DeleteVariable TABLE (FooID INT);
INSERT INTO @DeleteVariable (FooID)
        SELECT TOP 1 FooID FROM [BSystem].[Foo].[bar]
                ORDER BY CreateTimeUTC DESC;
DELETE FB 
        FROM [BSystem].[Foo].[fooBar] AS FB
        INNER JOIN @DeleteVariable AS DV ON (FB.FooID = DV.FooID);
DELETE B
        FROM [BSystem].[Foo].[bar] AS B
        INNER JOIN @DeleteVariable AS DV ON (B.FooID = DV.FooID);
于 2013-02-20T00:01:10.750 回答