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Forum:
Visual FoxPro
Category:
Coding, syntax & commands
Title:
Miscellaneous
Thread ID:
00445751
Message ID:
00445775
Views:
15
This message has been marked as a message which has helped to the initial question of the thread.
To get cross join, also called cartesian product, you do select from two tables w/o specifying join condition.

SELECT t1.State, t1.Town, t2.Period, t2.UserGrp FROM t1, t2 INTO TABLE t3

This way each record from table t1 will be joined with each record from table t2.


>Hi Sergey,
>
>Thanks for your response. Actually, I showed the whole number of iterations (e.g. 51*12*number of towns, for RI=42, for MA ~150). So, the total number of iterations for RI is 28512, still it took 1min.57 sec., which is really slow, I think.
>
>How can I create a cross join, it's not clear for me, (I thought about it too). Could you please help me here? Meanwhile I'll try the same test on my local drive.
>
>>Hi Nadya,
>>
>>1) The tables you are creatin are quite large: For RI for one year more than 1 million records.
>>2) Try to put result table on local drive and see what difference it makes.
>>3) Instead of calculating period and UserGrp for each record create cursor with 51 possible combination and than cross join it with resault of your select
>>
>>HTH
>>

>>>Hi everybody,
>>>
>>>I have a quite simple program for pre-populating a table. For RI it has 28152 iterations, for MA ~236000. For some reason, it works really slow (1min.56 sec. for RI, 27 min. for MA). I suspect server's problem, but our Network Administrator tells me, that server is ok. I tried switching order between scan...endscan and for...next. Once this program executes really fast, but then again worked very slow. Could you please tell, is something wrong with the code?
>>>How can I speed up this program?
>>>
>>> < snip >
>>>Thanks in advance.
--sb--
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