MS-Access错误：此子查询最多可返回一条记录

Question

当我尝试运行此查询时，它会给出错误“此子查询最多可以返回一条记录”

SELECT * from rosterTbl 
WHERE 
rosterTbl.CounsellorID IN (IIF (ISNULL([Forms]![ReportsGUI]![cmbCounsellor]) , (SELECT counsellorID FROM
[Main: Counsellors_Tbl]),[Forms]![ReportsGUI]![cmbCounsellor]))

Answer 1

对于您要完成的任务，您的查询应如下所示：

SELECT * from rosterTbl 
WHERE [Forms]![ReportsGUI]![cmbCounsellor] IS NULL
OR rosterTbl.CounsellorID 
IN (SELECT counsellorID FROM [Main: Counsellors_Tbl])