有条件的SQL条件

Question

为什么这样做..

DECLARE @SkyBlue Bit
SET @SkyBlue = 1
IF @SkyBlue
    Select 'the sky is blue!'
ELSE
    Select 'the sky is not blue!'

制作本

  

“非布尔类型的表达式   在上下文中指定的   条件是预期的，靠近'选择'。“

SQL2008中是否有布尔类型？

Answer 1

@SkyBlue有点，不是布尔值。尝试：

DECLARE @SkyBlue Bit
SET @SkyBlue = 1
IF @SkyBlue = 1
    Select 'the sky is blue!'
ELSE
    Select 'the sky is not blue!'

请注意，这也失败了

if 1
    Select 'the sky is blue!'
ELSE
    Select 'the sky is not blue!'