如何为 XML 编写包含联合逻辑的 SQL Select？

Question

我有以下语句将两个日期都输入@xmlData

declare @xmlData OUTOUT

SET @xmlData = (SELECT @FileDate AS [FileDate] UNION SELECT @satDate AS [FileDate] FOR XML RAW, ELEMENTS)

然后我会把它插入table:

DECLARE @ListOfDates TABLE (FileDate varchar(50))

        INSERT @ListOfDates (FileDate)
        SELECT Tbl.Col.value('FileDate[1]', 'varchar(50)') 
        FROM @xmlData.nodes('//row') Tbl(Col)

在执行我的 select 逻辑时，我收到一条错误消息：

The FOR XML and FOR JSON clauses are invalid in views, inline functions, derived tables, and subqueries when they contain a set operator. To work around, wrap the SELECT containing a set operator using derived table or common table expression or view and apply FOR XML or FOR JSON on top of it.

如何解决？

Answer 1

我完全不明白你为什么要在这里使用 XML。但错误是告诉您将该查询下推到派生的 table（子查询）或 CTE，如下所示：

declare @xmlData xml
declare @filedate date = getdate()
declare @satdate date = '20140101'

SET @xmlData = (

select * from 
( SELECT @FileDate AS [FileDate] UNION ALL SELECT @satDate AS [FileDate] ) d
FOR XML RAW, ELEMENTS, type

)

select @xmlData

如何为 XML 编写包含联合逻辑的 SQL Select？

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