Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
True, you can't do it in a single clean SELECT statement. However, there's a trick using UNIQUE indexes that takes care of this pretty nicely. I don't remember what it was exactly but I've listed a couple of articles from FoxTalk that might prove useful. Jinkerson & Grommes's trick uses the UNIQUE index idea.
May 1999:
Driving the Data Bus: Matchmaker, Mitchmoker ... Is That a Match? Or De-mystifying De-duplication, Andrew Coates
Finding duplicate entries in your data or matching records from different tables is a problem that has plagued database designers since databases began (and even earlier). In this article, Andrew demonstrates some of the techniques you can use to match records. Subscriber Source Code.
May 1997:
A "UNIQUE" Approach to De-Duping in FoxPro, Dave Jinkerson and Bob Grommes
Here's a simple and elegant approach to a seemingly difficult problem: removing duplicate records from a table.
Whil
Précédent
Suivant
Répondre
Voir le fil de ce thread
Voir le fil de ce thread à partir de ce message seulement
Voir tous les messages de ce thread
Voir tous les messages de ce thread à partir de ce message seulement