Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
VFP DATE() vs. SQL GETDATE()
Message
De
25/04/2006 09:59:04
 
 
À
25/04/2006 09:38:05
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP1
OS:
Windows XP SP2
Network:
Windows NT
Database:
MS SQL Server
Divers
Thread ID:
01115333
Message ID:
01116352
Vues:
19
Hi Tore,

>Pardon me for jumping in. You wrote "so I had tried: WHERE DATE()-31". This >is a terrible solution, even if it would have worked, because VFP, or MS->SQL, would have to evaluate DATE()-31 for every record! Always use >variables in where clauses, whenever possible. Use ldDate=date()-31 >followed by .. where datefield=ldDate.

Glad you jumped in ... I'm completely 'self-taught' and always welcome a correction to my education.

Let me make sure I understand ...

If I had used "WHERE DATE()-31" in the SQL statment ... the DB server would have to make that comparison for each record in the DB. But, if I store DATE()-31 into a variable, then SQL can skip the 'every record check' and immediately pull the records that contain the date stored in the variable (or, are within a date range provided by a couple of variables), correct?

I have known for a very long time that you can't (shouldn't) create a view on a large SQL table without parameters, as every record will come accross the LAN to the workstation. Therefore, I've always use variables, rather than selecting the whole table. However, I didn't realize that there was such a huge difference in putting a conditon in a WHERE clause or storing the results of the condition in a variable and then using the variable in the WHERE clause. When I think about it, this makes alot of sense but I had just missed this piece of knowledge.

Thanks,
Robert
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform