Re: Newbie ex-Oracle person's question: Oracle ROWID = PSQL OID, Orac le ROWNUM = PSQL ???

* Robert Beer <Robert.Beer@Callserve.com> menulis:
> Oracle has a ROWNUM pseudo column that works like this ...
> TEST>select callid, rownum from cs_calls where rownum < 5;
> 
>     CALLID     ROWNUM
> ---------- ----------
>       7806          1
>       7807          2
>       7809          3
>       6443          4
> 
> 4 rows selected.
> 
> ... which can be quite handy.
> 
> Is there something like this in PSQL?

You can use the LIMIT clause:

SELECT callid FROM cs_calls LIMIT 4;

See
<http://postgresql.readysetnet.com/users-lounge/docs/7.1/postgres/sql-select.html>
for more info.


> By the way, having used Oracle since 1987 it's a pleasure to use PSQL.
> Someone actually thinks about the implemented features.
> For example, Oracle's implementation of ROWNUM gives them in the order the
> rows were BEFORE the ORDER BY, which is not of much use as adding an ORDER
> BY jumbles them up.  Duh!

LIMIT in PostgreSQL applies *after* ORDER BY, so you won't have this
problem :)


-- 
Cliff Crawford   http://www.sowrong.org/
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