Re: RE:Re: A complex SQL query

Victor Yegorov <[email protected]> Sun, 8 Sep 2019 00:33:28 +0300

Newsgroups	gmane.comp.db.postgresql.sql
Message-ID	<CAGnEboib=bKnJsW9Ho_A0-fBoCzb2cxQp+oXHNxmoBrro+dS3w@mail.gmail.com>

сб, 7 сент. 2019 г. в 21:23, jj08 <[email protected]>:

> To Janis or other members of the forum:
>
> My sample table contains other columns as well.
>
> One of the columns that I did not include in my first message is
> "position".
> The last table has been modified as follows:
>
> +--------+----------+------------+------------------------+
> | usr_id | employer | position   + start_date | end_date  |
> +--------+----------+------------+------------------------+
> | A      | Goo      | CTO        |            | 201904    |
> | A      | Micro    | Mgr        | 201704     | 201903    |
>
> | B      | Micro    | Engg_Mgr   | 201706     | -         |
> | B      | Goo      | Researcher | 201012     | 201705    |
> | B      | Micro    | Postdoc    | 201001     | 201011    |
> +--------+----------+------------+------------------------+
>
SELECT DISTINCT ON (usr_id)
       *
  FROM employment
 WHERE employer='Micro'
 ORDER BY usr_id, start_date DESC;

-- 
Victor Yegorov