Kevin Jardine <kevinjard...@yahoo.com> writes:
> I have a query structured like this:
> SELECT stuff FROM
> (SELECT more stuff FROM
> table1
> ORDER BY field1) AS q1
> INNER JOIN table2 ON ( ... )
> and have found that the INNER JOIN is ignoring the order set for q1.
> The final results are not ordered by field1.
Indeed. Many of the possible join techniques won't preserve that ordering.
> This works for other databases (eg. MySQL and Sqllite3) but not PostgreSQL.
It might sometimes accidentally fail to fail, but I think you'll find
that there are *no* SQL databases where this is guaranteed to work the
way you expect. The SQL standard explicitly disavows any particular
output row order unless there is a top-level ORDER BY. (In fact,
unless things have changed recently an ORDER BY in a sub-select isn't
even legal per spec.)
> I can make some small changes to the query structure as long as it works for
> the other DBs as well. Moving the ORDER BY outside q1 would be a large amount
> of work, however (these queries are generated by a program), so I am hoping
> that there is a simpler solution.
Nope, that's what you need to do.
regards, tom lane
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