"at most one record can be returned by this subquery" 毫秒访问错误 sql

Question

我正在使用 ms access 数据库，但在执行 ms access 查询时出现此类错误 "at most one record can be returned by this subquery"。

查询是-

SELECT AccNumber, SimpleLoanBal, (select sum(MonthlyCollection) from Trans group by AccNumber) as Mo FROM Trans

请告诉我如何解决它

Answer 1

您可以改用 correlated 子查询：

select t.AccNumber, t.SimpleLoanBal, 
      (select sum(t1.MonthlyCollection) from Trans t1 where t.AccNumber = t1.AccNumber) as Mo 
from Trans t;

然而，简单的 group by 也应该有效：

select AccNumber, SimpleLoanBal, sum(MonthlyCollection) as Mo 
from Trans 
group by AccNumber, SimpleLoanBal;