sql-server - 关键字 'case' 附近的语法不正确

Question

这段代码有什么问题

CREATE FUNCTION [dbo].[ChangeRevision] (@oldRev tinyint)
RETURNS varchar(1) 
AS
begin

declare @newRev varchar(1)
DECLARE @newval int
set @newval=CAST (@oldRev as int)

case @newval
begin
when 0 then set @newRev='Z'
when 1 then set @newRev='A'
when 2 then set @newRev='B'
when 3 then set @newRev='C'

end
return @newRev;

END

我有以下错误 关键字“case”附近的语法不正确。

关键字“Return”附近的语法不正确。

Answer 1

这应该有效:

SET @newRev = (SELECT case @newval
    WHEN 0 THEN 'Z'
    WHEN 1 THEN 'A'
    WHEN 2 THEN 'B'
    WHEN 3 THEN 'C'
    END)