检查SQL Server 2005 XML字段是否为空

Question

我这样做了:

Delete FROM MyTable WHERE ScopeValue = "" 
Delete FROM G_Scope WHERE ScopeValue is ''
Delete FROM G_Scope WHERE ScopeValue = empty
Delete FROM G_Scope WHERE ScopeValue is empty

我想用xml字段删除所有行(不可为空),其中ScopeValue列有空条目表示零字符.

有谁知道？

Answer 1

试试这个:

 DELETE FROM dbo.G_Scope WHERE ScopeValue IS NULL

NULL如果不包含任何值,SQL Server列将是.

另一种可能性是XML不是NULL,而是包含一个空字符串作为其值.为此,请使用此命令:

-- The DATALENGTH of an empty XML column is 5
SELECT * FROM dbo.G_Scope WHERE DATALENGTH(ScopeValue) = 5

这会显示您感兴趣的行吗？