Re: [Firebird-devel] Using DISTINCT and ORDER

[Arno B. <fbd...@ab...>]

Hi,

> I often use it with lazy loading - first I only load PK values in some
> order, ie
> SELECT DISTINCT PK FROM Customers WHERE(..) ORDER BY Name
> and later when I need details I use the PK to load full record. It
> would be overkill to include ordering fields into original query's
> select list.

The DISTINCT is overkill here, because the PK is unique.

This would be fine:
SELECT PK FROM Customers WHERE(..) ORDER BY Name

but this isn't:

SELECT DISTINCT PK FROM Customers WHERE(..) ORDER BY Name

Be prepared that the query will raise an error in the future! 
So change it to a correct query.
In fact DISTINCT <list> and GROUP BY <list> are the same. You'll see that with GROUP BY an error is thrown.

Regards,
Arno Brinkman
ABVisie

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