Hi Nick,

How many records in the table? How many records approximately match each condition?
BTW, you don't need index on LEFT(OrdNo,1). You can use LIKE instead

SELECT TOP 1 OrdNo FROM Orders ;
  WHERE OrdNo > cLastOrdNo AND OrdNo LIKE cDept + "%" ;
  ORDER BY OrdNo

>
>I have a problem whereby Rushmore seems to fail on a largeish table; 100k records 200 fields. Once the table goes beyond a certain size MIN(), MAX() and TOP 1 simple seem to stop being optimized properly even though SYS(3054) still indicates that it is being optimized.
>
>An example:
>* note Orders is 100k records and 200 fields wide
>* Indexed on OrdNo and LEFT(OrdNo,1)
>
>* This takes 50 seconds
>SELECT TOP 1 OrdNo FROM Orders WHERE OrdNo > cLastOrdNo ;
> AND Left(OrdNo,1) = cDept ORDER BY OrdNo
>
>* but seperate into a narrower table
>SELECT OrdNo FROM Orders INTO TABLE OrdersNoOnly
>INDEX ON OrdNo TAG OrdNo
>INDEX ON LEFT(OrdNo,1) TAG Dept
>
>* This takes 0.7 seconds although the table is still 100k records long
>SELECT TOP 1 OrdNo FROM OrdersNoOnly WHERE OrdNo > cLastOrdNo ;
> AND Left(OrdNo,1) = cDept ORDER BY OrdNo
>
>Has anyone ever encountered anything similar?