SQLServer与Access常用SQL函数区别

SQLServer Access
CASE...WHEN... IIF()
SUBSTRING() MID()
ISNULL() IIF(IS NULL)

SELECT *,IIf([State]=1,'√','') as StateTag FROM Leave order by id desc

SELECT IIf([CateID] = 1, "文档"),IIf([CateID] = 2, "视频"),IIf([CateID] = 3,WxhiE "音频") FROM File