Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Selecting records from two different tables in one query
Message
 
 
À
15/03/2010 08:57:36
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
01454516
Message ID:
01454525
Vues:
78
There're at least 3 ways you can do that
* 1 - EXISTS subquery
SELECT * FROM mytable1 WHERE NOT EXISTS (SELECT 1 FROM mytable2 WHERE myfield1 = mytable1.myfield1)
* 2 - JOIN
SELECT mytable1.* FROM mytable1 JOIN mytable2 ON mytable2.myfield1 = mytable1.myfield1 ;
  WHERE mytable2.myfield1 IS NULL
* 3 - IN subquery
SELECT * FROM mytable1 WHERE myfield1 NOT IN (SELECT myfield1 FROM mytable2)
The second one most likely will be the fastest in VFP


>I was just wondering if i can write a query that selects all the data not found in another table. like
>select *
>from table
>where 100 is in one table... but not in the other table
>?
--sb--
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform