sql - 如何修复 "Only one expression can be specified in the select list when the subquery is not introduced with EXISTS"错误？

Question

我正在尝试在 MS SQL 2012 Express 上运行以下查询:

Select (
    Select Id, Salt, Password, BannedEndDate
    from Users
    where username = '" + LoginModel.Username + "'
), (
    Select Count(*)
    From LoginFails
    where username = '" + LoginModel.Username + "'
    And IP = '" + Request.ServerVariables["REMOTE_ADDR"] + "')"
);

但是我收到以下错误:

Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.

如何解决这个问题？

Answer 1

试试这个:

 Select 
    Id, 
    Salt, 
    Password, 
    BannedEndDate, 
    (Select Count(*) 
        From LoginFails 
        Where username = '" + LoginModel.Username + "' And IP = '" + Request.ServerVariables["REMOTE_ADDR"] + "')
 From Users 
 Where username = '" + LoginModel.Username + "'

并且我强烈建议您在查询中使用参数，以避免 SQL 注入(inject)攻击的安全风险!

希望有帮助!