Re: Efficient DELETE Strategies

Manfred Koizar wrote:
> On Tue, 11 Jun 2002 10:28:40 -0400, Tom Lane <tgl@sss.pgh.pa.us>
> wrote:
> >It would seem that
> >
> >    DELETE [ FROM ] relation_expr [ alias_clause ]
> >    [ FROM from_list ] where_clause
> >
> >is the syntax that would be most nearly compatible with MSSQL and MySQL.
> >Does Oracle have anything comparable?
> 
> Oracle basically supports (with slight variations between releases
> 7/8/9):
>     DELETE [FROM] { table
>                   | view
>                   | ( subquery )
>                   }
>            [alias] [WHERE ...] [returning_clause]
> 
> Informix (March 1997, 9.1?):
>     DELETE FROM { table
>                 | ONLY ( table )
>                 | view
>                     | synonym
>                 | collection_derived_table
>                 }
>            WHERE condition
> 
> According to the "SQL Quick Syntax Guide" the WHERE clause is not
> optional.  Does anybody know, if this is a documentation bug?
> "Guide to SQL, Syntax" (Feb 1998, v7.3, v8.2) says, the WHERE clause
> is optional, as we'd expect.

Informix in dbaccess prompts you if you do a DELETE with no WHERE to
make sure it is what you want, if I remember correctly.  In app code,
the WHERE is optional.  At least that is how I remember it.

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