我希望我的数据库表中具有 NULL 的列将其设为空白

Question

我在 sql server 2008 中创建了一个存储过程，其中显示了来自同一数据库中两个不同表的列。我想将列中的 NULL 值替换为空白。任何人都可以帮助我吗？

    AlTER PROCEDURE sp_Test123  --sp_Test123
AS
BEGIN
SELECT MediaContentType.MediaContentTypeID as ID, 
MediaContentType.FileExtension,
IQCategory.Description,IQSubCategory.IQSubDesription
FROM MediaContentType
LEFT JOIN IQCategory
ON MediaContentType.MediaContentTypeID =IQCategory.IQCategoryID
LEFT JOIN IQSubCategory
ON MediaContentType.MediaContentTypeID = IQSubCategory.IQSubCategoryID

END

Answer 1

如果您需要在查询中替换 Null 值，那么这很容易。

你必须使用IsNull函数。

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SELECT MediaContentType.MediaContentTypeID as ID, 
ISNULL(MediaContentType.FileExtension,'') as FileExtension,
ISNULL(IQCategory.Description,'') as Description
ISNULL(IQSubCategory.IQSubDesription,'') as IQSubDesription
FROM MediaContentType
LEFT JOIN IQCategory
ON MediaContentType.MediaContentTypeID =IQCategory.IQCategoryID
LEFT JOIN IQSubCategory
ON MediaContentType.MediaContentTypeID = IQSubCategory.IQSubCategoryID

如果要更新表中的空值，请使用更新语句。

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Update MyTable
Set MyNullColumn = ''
where MyNullColumn Is Null