Question

我想验证该客户是否存在员工;如果他确实存在，那么我想要显示一条消息＆＃34;成功＆＃34;，否则我想显示＆＃34;无效的员工＆＃34;。

declare @Employeeid int

if @Employeeid = 1616
    select 
        @Employeeid = employeeindex 
    from 
        Employee_table
    where 
        clientid in (select Clientid 
                        from Employee_table 
                        where Clientid = 658)

    select * 
    from Employee_table 
    where Employeeid = @Employeeid

else
    raiserror ('Invalid Employee!', 16, 1)

return

这显示错误

关键字＆＃39;其他＆＃39;附近的语法不正确。

Answer 1

包含一系列Transact-SQL语句，以便可以执行一组Transact-SQL语句。 BEGIN和END是流控制语言关键字。

Read here

查询

declare @Employeeid int

if @Employeeid = 1616
begin
    select @Employeeid = employeeindex 
    from Employee_table
    where clientindex in (select Clientid 
                          from Employee_table 
                          where Clientid = 658)

    select * 
    from Employee_table 
    where Employeeid = @Employeeid
end
else
    raiserror ('Invalid Employee! ', 16,1)

return

Answer 2

https://docs.microsoft.com/en-us/sql/t-sql/language-elements/if-else-transact-sql

强制执行Transact-SQL语句的条件。的的遵循IF关键字的Transact-SQL语句及其条件是如果条件满足则执行：布尔表达式返回 TRUE

如果需要IF的组声明

，请使用BEGIN ... END

select语句中的if / else条件

2 个答案: