Yes, that's exactly what works for me.
Thanks a bunch!!!
--From: janis@puris.lv
--To: pgsql-sql@lists.postgresql.org,jj08@drivehq.com
--Date: 9/6/2019 5:56:10 AM
--Subject: Re: A complex SQL query
I hope someone can give me some pointers.
Here is my table.
+--------+----------+------------+-----------+
| usr_id | employer | start_date | end_date |
+--------+----------+------------+-----------+
| A | Goo | 201904 | - |
| A | Micro | 201704 | 201903 |
| B | Micro | 201706 | - |
| B | Goo | 201012 | 201705 |
| B | Micro | 201001 | 201011 |
+--------+----------+------------+-----------+
I am trying to list up people working for a company called "Micro".
Some people work for a company multiple times, like user B.
I only need one line per user, displaying only the latest affiliation date.
For user_id "B", I could do Select user_id, MAX(start_date), end_date where employer = 'Micro',
but that would fail to get record for user_id "A".
If multiple records exist, I want to do MAX, but if only a single record exists, I don't need MAX.
How do I do that?
From the above data, I would like to see only two lines:
| A | Micro | 201704 | 201903 |
| B | Micro | 201706 | - |
Thank you.
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