Re: simulate union in subselect

Wei Weng writes:

> I know this is not do-able, but is there any way to simulate the
> following in Postgresql 7.1?
>
> select id from
> (select id, recv_date as date from table1
> union
> select id, send_date as date from table2) AS subtable
> order by date;

I haven't actually tried whether this does not work, but ISTM that you
could simply do

select id, recv_date as date from table1
union
select id, send_date as date from table2
order by 2;

and ignore the second column when processing the result.

--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter