如何编写存储过程中传递多个参数

您好，

像我写
存储过程

ALTER proc [dbo].[testmultiplevalues](@emailid varchar(max)=null, @currlocation varchar(max)=null,@gender varchar(max)=null)

as

begin

declare @selquery varchar(max)

declare @concat varchar(max)

set @concat = ' '

set @selquery='select Emailid, currentlocation,Gender from userdetails where '

if(@emailid is not null)

begin

set @selquery=@selquery + 'Emailid=' +@emailid

set @concat=' and '

end

if(@currlocation is not null)

begin

set @selquery=@selquery + @concat + 'currentlocation=' +@currlocation

set @concat=' and '

end

if(@gender is not null)

begin

set @selquery =@selquery + @concat +'Gender=' + @gender

end

exec @selquery

end