在日期时间创建一个计算列 [英] Create a computed column on a datetime

问题描述

我在SQL Server 2005表中有一个可为空的DateTime列，称为DateTimeDeleted。

I have a nullable DateTime column in my SQL Server 2005 table called DateTimeDeleted.

我希望有一个BIT类型计算列，如果DateTimeDeleted为不是null，否则为0。但是，我似乎无法正确理解公式的语法。

I'd like to have a BIT type computed column that is 1 if DateTimeDeleted is not null, otherwise 0. However, I can't seem to get the syntax for the formula correct.

我尝试过：

(TsDeleted IS NULL) = 0

但是它给了我一个语法错误。

but it gives me a syntax error.

帮助！ ：）

推荐答案

Alter Table MyTableName 
  Add IsDeleted As 
     (Case When [DateTimeDeleted] Is Null 
       Then (0) Else (1) End)

这将输出为整数...如果您真的希望它有点，那么：

This will output as an integer... If you really want it to be a bit, then:

Alter Table MyTableName 
  Add IsDeleted As 
     cast( (Case When [DateTimeDeleted] Is Null 
       Then (0) Else (1) End) as Bit)

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