I am sure there is a more efficient way to do it, but I have never
had to do it with more than 1000 records so I have never needed to
optimise it further.

delete
from tableA
where code in
(
select code
from tableA a, tableA b
where a.code > b.code
and a.descr = b.descr
)

You may want to check the subselect first.

Adam




--- In firebird-support@yahoogroups.com, "Clay Shannon"
<cshannon@d...> wrote:

> Who knows how to delete duplicate values in a column via SQL. Some

of the

> goofy data I ported over from an MS Access "database"
>
> Has duplicate values in a Code/Description table (different codes,

same

> descriptions). I want to leave just one record for each distinct
> description. IOW, instead of
>
>
>
> CODE DESCRIPTION
>
> 01 TUBERCULOUS PLEURISY IN PRIMARY
> PROGRESSIVE TUBERC
>
> 02 TUBERCULOUS PLEURISY IN PRIMARY
> PROGRESSIVE TUBERC
>
> 10 TUBERCULOUS PLEURISY IN PRIMARY
> PROGRESSIVE TUBERC
>
> 11 TUBERCULOUS PLEURISY IN PRIMARY
> PROGRESSIVE TUBERC
>
>
>
> I want to end up with just:
>
> CODE DESCRIPTION
>
> 12 TUBERCULOUS PLEURISY IN PRIMARY
> PROGRESSIVE TUBERC
>
>
>
> Or so..
>
>
>
>
>
> Clay Shannon,
>
> Dimension 4 Software
>
>
>
>
>
> [Non-text portions of this message have been removed]