asp.net - SQL Server：声明导致查询出现问题

Question

我目前有一个我无法弄清楚的 SQL Server 问题。

错误是：

为变量赋值的 SELECT 语句不得与数据检索操作结合使用

SQL：

DECLARE @IdUser INT 

Select 
    @IdUser = Id, 
    Username, 
    (Select Count(*) From GagsLikes where Userid = @IdUser And Good = 1) as GagLikes, 
    (Select Count(*) From GagsViews where UserID = @IdUser), 
    (Select Count(*) From Gags Where UserID = @IdUser) as GagViews 
From 
    Users  
Order by 
    GagLikes, GagViews

提前致谢！

Answer 1

您可能不会在执行此操作时使用该变量，请尝试以下操作：

Select 
    U.Id, 
    U.Username, 
    (Select Count(*) From GagsLikes where Userid = U.Id And Good = 1) as GagLikes, 
    (Select Count(*) From GagsViews where UserID = U.Id), 
    (Select Count(*) From Gags Where UserID = U.Id) as GagViews 
From 
    Users AS U
Order by 
    GagLikes, GagViews

Answer 2

您的表可能会返回多于一行。确保您的表只返回一行，否则它无法将多个 id 存储到一个 int 变量中。