Re: union with count?

[Richard Broersma Jr <rabroersma(at)yahoo(dot)com>]

--- Gerardo Herzig <gherzig(at)fmed(dot)uba(dot)ar> wrote:

> Hi dudes, i have the following question
> i have 2 tables with the same format, and i want to know if is there a 
> possibility of using some sort of count(*) for achieving this result:
> select a from table1 where (condition) union select a from table2 where 
> (condition), count(a) group by a

I think you are showing count(a) in the wrong spot in your example.  But if I understand you
correctly the following should do what you want:

SELECT count(a)
FROM
(
    SELECT a
    FROM table1
    WHERE (your_condition = true)

UNION -- you can use UNION ALL if you 
      -- want rows that are duplicates from each table.

    SELECT a
    FROM table2
    WHERE (your_condition = true)
)
GROUP BY a;