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Can this be done in one SQL Select?
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À
08/02/2005 18:34:29
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00984864
Message ID:
00984979
Vues:
20
>>I need help in selecting records from the following table (simplified):
>>
>>CUST_ID
>>ORD_DATE
>>ORD_TIME
>>
>>For a given date (ORD_DATE), I need to select one order record per customer (CUST_ID) based on the time of order (ORD_TIME). For example, the Order Time should be the latest of the day.
>>
>>I would appreciate any suggestions.
>>
>>Thank you.
>
>Every time I've tried something like this in one statement I wind up with a sluggish pig of a query. Breaking it into two steps seems to work much better for me
>
>
>SELECT cust_id,ord_date,MAX(ord_time) FROM myTable;
> GROUP BY cust_id,ord_date;
> INTO CURSOR tmpCur
>
>SELECT myTable.* FROM myTable,tmpCur ;
> WHERE myTable.cust_id = tmpCur.cust_id;
>   AND myTable.ord_date = tmpCur.ord_date;
>   AND myTable.ord_time = tmpCur.ord_time
>
Thank you so much for your suggestion.
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