>>>>Hi Nadya,
>>>>
>>>>Integers do return wrong results in some versions of VFP in few situations if you are using a collate sequence different from MACHINE.
>>>>
>>>>Christof
>>>
>>>Hi Christof,
>>>
>>>How can I check the collate sequence for the indexes in my tables? I thought, they are machine, but now I need to check.
>>>
>>>Thanks in advance.
>>>
>>>Found it: IDXCOLLATE() function
>>
>>list STRUCTURE
>
>They are both MACHINE. Should I re-build them? Do you see any problem in this simple SQL which may cause this strange behavior?

I don't see anything wrong with your select. Are you sure that data in Jobs and Customer tables is correct? You can certanly try to rebuild indexes.