如何删除具有最小值和最大值的空值的列

由于 OP 对任何数据样本没有帮助，我所理解的是 OP 想要删除包含 NULL 值的超时。所以我只是使用派生表来过滤掉具有 NOT NULL 值的超时。

     SELECT * FROM (select A.EmpID [X_TMSHT_EMPID] ,convert (varchar,(A.[RecordDate]),1) [X_TMSHT_APPLY],  
      , (convert(varchar,(A.[RecordDate]),1) + ' ' +( MAX(IIF(ISNULL(CHARINDEX('O', A.[Entries], 0), -1) > 0,SUBSTRING(A.[Entries], LEN(A.[Entries]) - 5, 5), NULL)))) AS [TimeOut]
    FROM Employees[B]
    inner JOIN[DTR Upload] [A] ON B.EmployeeNo = A.EmpID 

    ) AS d
    WHERE d.TimeOut IS NOT NULL
GROUP by d.LastName, d.FirstName, d.MiddleName, d.EmpID, d.[recordDate]
    order by d.[recordDate] asc