>>>SYS(11) return a fixed lenght string C(7),
>>>
>>
>>Are you sure?
>>
>>

>>? LEN(SYS(11,'06/06/1998'))
>>? LEN(SYS(11,{}))
>>

>>
>>Thanks,
>>Aleksey.
>
>This wouldn't be such a big deal to us if SET ENGINEBEHAVIOR 70/80 actually switched the optimization behavior back to 7 or 8. In this case, however, it doesn't.

If you have an empty date the use of the index returns a wrong result:

* on VFP8
SYS(3054, 11)
SET ANSI OFF
CLEAR
CREATE TABLE c:\testopt (trans_date D)
APPEND BLANK

test()

 
INDEX ON SYS(11,trans_date) TAG custhist

test()

PROCEDURE test
SELECT * ;
	INTO ARRAY x;
  FROM testopt;
 WHERE SYS(11,trans_date) = "01"
? _tally