On 4/8/06, Tom Lane <[EMAIL PROTECTED]> wrote:
> A function implemented as per Michael's example would not give the
> results that I think people would expect for
>
> SELECT rownum(), * FROM foo ORDER BY whatever;
>
Yep, the query would have to be rewritten similar to Oracle's:
SELECT rownum(), * FROM (SELECT * FROM foo ORDER BY whatever);
IIRC, processing-wise, rownum and order-by processing is handled as follows:
SELECT id, whatever FROM foo WHERE rownum <= 10 ORDER BY id;
is the same as PostgreSQL's
SELECT id, whatever FROM (SELECT id, whatever FROM foo LIMIT 10) ORDER BY id;
--
Jonah H. Harris, Database Internals Architect
EnterpriseDB Corporation
732.331.1324
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
