Question

declare @Maxamount int,
        @month varchar,
        @Duration int,
        @iReturn int

set @month = (select DATEPART(MM,start_date) from TC_Project_Referal where id_tc_projuser = @id_tc_projuser)
set @Duration = (select fixeddDuration from TC_Project_Referal where id_tc_projuser = @id_tc_projuser)

select @Maxamount = @month+@Duration-1

子查询返回的值超过1。当子查询遵循=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或子查询用作表达式时，不允许这样做。我在数据库中有超过1条记录。数据将根据ID显示。我们也可以为单个id提供多个记录。然后如何

Answer 1

使用INTO。

select DATEPART(MM,start_date) **into** @month from TC_Project_Referal where id_tc_projuser = @id_tc_projuser;

select fixeddDuration **into** @Duration from TC_Project_Referal where id_tc_projuser = @id_tc_projuser;

select @Maxamount := @month+@Duration-1;

Answer 2

如果您的内部查询碰巧返回多行，则会出现以下错误

子查询返回的值超过1。这是不允许的子查询跟随=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或当子查询用作表达。

确保查询使用TOP子句

返回单个记录

declare @Maxamount int,
        @month varchar,
        @Duration int,
        @iReturn int

set @month = (select TOP 1 DATEPART(MM,start_date) from TC_Project_Referal where id_tc_projuser = @id_tc_projuser order by start_date)
set @Duration = (select TOP 1 fixeddDuration from TC_Project_Referal where id_tc_projuser = @id_tc_projuser order by id_tc_projuser )

select @Maxamount = @month+@Duration-1

如何添加标量变量并将结果存储在另一个标量变量中

2 个答案: