On Fri, Jan 17, 2003 at 08:57:14 -0500,
Andrew Perrin <clists(at)perrin(dot)socsci(dot)unc(dot)edu> wrote:
> I'd suggest something similar to, but slightly different from, what others
> have:
>
> SELECT DISTINCT email FROM (SELECT email FROM table_1 UNION SELECT
> email FROM table_2) AS combined;
>
> that way you avoid duplicates across tables.
The union operator already removes duplicates.