这个T-SQL语句有什么问题？

Question

Why is this throwing an error on the equal sign?

select IIF((SUBSTRING('A1234', 1, 1) = 'A'), TRUE, FALSE) as IsAustraliaUser

Error:

Msg 102, Level 15, State 1, Line 1
Incorrect syntax near '='.

Answer 1

IIF is a SQL Server 2012 feature, you'll need to use CASE

SELECT CASE SUBSTRING('A1234', 1, 1)
       WHEN 'A' THEN 'TRUE'
       ELSE 'FALSE'
       END

Answer 2

你应该用CASE替换IIF，在SQL Server中也不存在TRUE和FALSE，你可以使用VARCHAR或BIT

select CASE WHEN SUBSTRING('A1234', 1, 1) = 'A' THEN 'TRUE' ELSE 'FALSE' END as IsAustraliaUser

Answer 3

I don't think SQL supports this syntax of IIF (unless you're using 2012), replace with case.

SELECT  CASE WHEN ( SUBSTRING('A1234', 1, 1) = 'A' ) THEN 'TRUE'
             ELSE 'FALSE'
        END AS IsAustraliaUser