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QUERIES/SELECT - SQL Info
Message
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
00520717
Message ID:
00520790
Vues:
16
A couple things that helped me...

1. A Visual Introduction to SQL published by Wiley. Had my "Aha" experience working with this book. It was one of the first books published on generic SQL rather than a specific implementation. Pretty basic, at this point, though.

2. If you're using NDX indices that are open and not up to date, you will have problems with missing data if SELECT uses them.

3. VFP SELECT evaluates conditions at a different point in processing, depending on whether they're in the JOIN or in the WHERE clause. If you need evaluation of data before the join, stick the condition in the JOIN clause. If you need it after the join, use the WHERE.

The FoxWiki may have more info on this. Haven't checked.


Jay

>Is there a good place to find a good source of how SELECT-SQL works in VFP 6.0 with examples? I have read the Hackers quide but there has to be something missing. My queries usually work fine but every now and then items get left out. I know because I get the info by hand and compare it to the select statement and find that things are just missing.
>
>Any help in this area would really be appreciated.
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