Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Which SQL Select would be faster?
Message
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Versions des environnements
Visual FoxPro:
VFP 9 SP1
Divers
Thread ID:
01095983
Message ID:
01096103
Vues:
17
This message has been marked as a message which has helped to the initial question of the thread.
>>Here's one more for you
>>
>>select * FROM PARENT p
>>	JOIN (SELECT distinct PK_FLD FROM CHILD WHERE(&cChildFilter)) dt1
>>		ON dt1.PK_fld = p.PK_fld
>>
>>
>
>I think I see where your approach is better. In your SQL Select, VFP has to "query" CHILD table only once. In my approach, SQL Select has to "jump" from quering PARENT to CHILD and back.

Hi Dmitry,

In VFP the queries with JOIN usualy faster than with correlated EXISTS subqueries. The opopsite is true for MS SQL Server.
--sb--
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform