Question

子查询返回的值超过1。当子查询遵循=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或子查询用作表达式时，不允许这样做。

CREATE PROCEDURE list_select (@id INT)

AS

IF (@id IS NOT NULL)
BEGIN
    DECLARE @xml XML = CAST((SELECT data FROM messages WHERE id = @id) AS XML)
    DECLARE @reference VARCHAR(MAX) =  @xml.value('(/*:xml/*:reference/text())[1]', 'varchar(50)')
    DECLARE @name VARCHAR(MAX) = @xml.value('(/*:xml/*:name/text())[1]', 'varchar(50)')

END

SELECT
    @reference as reference,
    @name as name
GO

如何才能使用多个值？

Answer 1

我认为 for xml path做你想做的事：

DECLARE @xml XML = (SELECT data FROM messages WHERE id = @id FOR XML PATH (''))

子查询使用XML强制转换返回了多个值

1 个答案: