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Subquery in UPDATE SQL?
Message
De
15/07/2004 16:19:46
 
 
À
15/07/2004 14:24:42
John Baird
Coatesville, Pennsylvanie, États-Unis
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00924713
Message ID:
00924901
Vues:
12
Are you going to correct your post to Brenda?

>Thanks... learn something new everyday...
>
>
>
>>Try this
>>
>>------------------------------------------------------------------
>>* TestUpdateSubQuery.prg
>>
>>LOCAL i
>>
>>#DEFINE TEST_RECORD 10
>>
>>CREATE TABLE TestUpdate FREE ( ;
>> pkey i( 4 ), ;
>> datavalue i( 4 ) ;
>> )
>>
>>FOR i = 1 to 10 STEP 1
>> INSERT INTO TestUpdate ( pkey, datavalue ) ;
>> VALUES ( i, i )
>>ENDFOR
>>
>>SELECT * FROM TestUpdate
>>
>>SELECT * FROM TestUpdate WHERE pkey == TEST_RECORD INTO CURSOR rcurRefUpdate
>>
>>UPDATE TestUpdate ;
>>SET datavalue = GetNewValue() ;
>>WHERE pkey IN ( ;
>> SELECT pkey FROM rcurRefUpdate ;
>> )
>>
>>SELECT * FROM TestUpdate
>>
>>CLOSE ALL
>>
>>RETURN .T.
>>
>>
>>FUNCTION GetNewValue()
>>
>>RETURN 25
>>
>>----------------------------------------------------------------------
>>
>>This is a simple example, but it illustrates that a column in a subset of rows can be updated (to a single value) in this fashion.
>>
>>Hope this helps,
>>
>>John
-=Gary
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