在视图sql server中设置具有默认值的动态列。 [英] set dynamic column with default value in view sql server.

问题描述

我在SQL Server中有一个视图，动态添加一个默认值的列！如何在View中定义默认值列？

I Have a View in SQL Server, dynamically add one column with default value! How Can I define a default Value Column in View?

推荐答案

如果您需要默认值的列需要NULL时的值，请使用ISNULL函数：



SELECT a，b，ISNULL（c，'DEFAULT'）AS c FROM xyz



如果您需要默认情况下，当字段为空，有一些标记值或其他任何使用CASE / END结构时（这有点复杂，所以你应该阅读文档，但是类似于：



SELECT a，b，CASE c WHEN NULL THEN'Null'When''Then'Full'ELSE c END as c from xyz

If the column you need a default for requires a value when NULL, use the ISNULL function:

SELECT a, b, ISNULL(c, 'DEFAULT') AS c FROM xyz

If you need the default when the field is blank, has some sentinel value or anything else use the CASE/END construct (this is a little more complex, so you should read the documentation, but something like:

SELECT a, b, CASE c WHEN NULL THEN 'Null' WHEN '' THEN 'Blank' ELSE c END AS c FROM xyz

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