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Base de données, Tables, Vues, Index et syntaxe SQL
>I'm often confused by whether I need to include all the fields I mention in my WHERE clauses when selecting fields for the result set, and it's just now coming to a head - perhaps someone here could clarify for me.
>
>Let's say for example I want a list of all the items ever purchased by a client, and those items are linked to the client number through a long tree:
>
>Clients ---- Invoices ---- InvDetail ---- Items
>
>Can I get this list by saying:
>
>SELECT Items.ItemName FROM Items, InvDetail, Invoices ;
> WHERE Invoices.ClientNo = "12345" ;
> AND InvDetail.InvoiceNo = Invoices.InvoiceNo ;
> AND Items.ItemNo=InvDetail.ItemNo ;
> ORDER BY 1 ;
> INTO CURSOR JustItems
>
>... or do I need to include clientno, both invoiceno's and both itemno's in the field list?????
>
>TIA
You can do something similar without having to include the fields by using joins instead.
Dan
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