Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Another Subquery Problem
Message
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
00053707
Message ID:
00053955
Vues:
40
OK gentlemen, I restarted my workstation fresh and did some more testing on this issue of EXISTS vs IN. I took the first 2 queries of my code using EXISTS and the same queries using IN and alternated between running each of them. I ran all four a total of 5 times and calculated the following averages using only this batch of test runs:

Using EXISTS:
1st Query = avg 225.67 seconds
2nd Query = avg 297.89 seconds

Using IN:
1st Query = avg 266.40 seconds
2nd Query = avg 326.15 seconds

So I'm seeing approx. 30 seconds difference here, with EXISTS being faster. (and seriously doubting I could prove 2 Fox Gods wrong this easy) If I have time tomorrow I might try this exercise again on the server, to eliminate any question of untimely network traffic.

So what's your opinion now? Still think IN is faster/better performance? People always say my environment is abnormal so I wont be insulted if you tell me this example doesnt change your opinion :D) Also, do you think that since I'm using 2.6 tables as free tables in VFP has an effect on these results? Someday I'll have all my tables in a VFP dbc, and thats when I'll really put what I learned with this thread to use. TIA for your all your help and valuable opinions.
Roxanne M. Seibert
Independent Consultant, VFP MCP

Code Monkey Like Fritos
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform