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Understanding SQL Select
Message
De
02/03/2009 20:23:49
 
 
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:
01385138
Message ID:
01385139
Vues:
143
This message has been marked as the solution to the initial question of the thread.
>Hi,
>
>Here is a pseudo SQL Select statement:
>
>
>select field1, field2, ... from Table1 left join Table2 on Table1.fieldX = Table2.fieldX where (Long Expression)
>
>
>From running this type of SQL Select and analyzing results, it seems to me that VFP will first do the LEFT JOIN and then apply the WHERE condition to the resulting query. Is this correct?
>
>My question is, how do you make the SQL Select to select records from Table1 based on the Long Expression and then LEFT JOIN the resulting query?

Add any conditions from the long expression that involve fields of Table2 to the ON clause.
SELECT field1, field2, ... ;
  FROM Table1 ;
    JOIN Table2 ;
      ON Table1.FieldX = Table2.FieldX ;
       AND Table2.FieldY > Something ;
  WHERE Table1.FieldZ = SomethingElse
Tamar
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