SELECT ;
    CustNo, Customer, QtyIn, QtyOut, QtyIn-QtyOut As QtyDiff ;
      FROM ( ;
         SELECT ;
            cs.CustNo, ;
            cs.Customer, ;
            SUM(si.StandsIn) AS QtyIn, ;
            SUM(so.SerialCnt) As QtyOut ;
               FROM Customer cs ;
                  LEFT JOIN StandsIn si ON si.cust = cs.CustNo ;
                  LEFT JOIN Stands_Out so ON so.cust = cs.CustNo ;
               GROUP BY ;
                  cs.CustNo, ;
                  cs.Customer ;
       ) dt1

>
>I am not very good at these SQL statements as can be seen below:
>
>

>SELECT ;
>    Cust, Customer, QtyIn, QtyOut, QtyIn-QtyOut As QtyDiff ;
>      FROM ( ;
>         SELECT ;
>            CustNo As Cust, ;
>            Customer, ;
>            SUM(si.StandsIn) AS QtyIn, ;
>            SUM(so.SerialCnt) As QtyOut ;
>               FROM Customer cs ;
>                  LEFT JOIN StandsIn si ON si.cust = cs.cust ;
>                  LEFT JOIN Stands_Out so ON so.cust = cs.cust ;
>               GROUP BY ;
>                  Cust, ;
>                  Customer ;
>       ) dt1;
>*WHERE QtyOut > QtyIn ;
>

>"CustNo" is the name of the Customer ID in the Customer table; elsewhere it is "Cust".
>
>I get the following error: "SQL: Column 'Cust' is not found."