agora inbox for pgsql-sql@postgresql.org
help / color / mirror / Atom feedFrom: jj08 <jj08@drivehq.com>
To: pgsql-sql@lists.postgresql.org
To: pgsql-sql-owner+M68182-176663@lists.postgresql.org
To: janis@puris.lv
Subject: RE:RE:Re: A complex SQL query
Date: Sat, 07 Sep 2019 11:23:20 -0700
Message-ID: <2260908401000000009736706@www> (raw)
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 |
+--------+----------+------------+------------------------+
Explanation:
B joined Micro as a postdoc in 201001. After 11 months (201011), he quit and moved to Goo as a researcher.
After about 6.5 years, he came back to Micro, this time, as an engineering manager.
Problem:
I want to retrieve position as well, but I cannot add 'position' to the select part.
//----------------------------------------------------------------------------------
select
user_id,position,
max(position_start) as position_start, case when max(position_end) < max(position_start) then null else max(position_end) end as position_end<br />
from
employer
where
employer= 'Micro'
group by
user_id;
//-------------------------------------
This results in error:
"ERROR: column "employer.position" must appear in the GROUP BY clause or be used in an aggregate function
When I add position to the group by clause, like this:
//----------------------------------------------------------------------------------
select
user_id,position,
max(position_start) as position_start, case when max(position_end) < max(position_start) then null else max(position_end) end as position_end<br />
from
employer
where
employer= 'Micro'
group by
user_id, position;
//-------------------------------------
I get two records for B, both when he was a postdoc back in 201001, and Engg_Mgr (201706).
I only need the latest/single entry (the whole point I wanted to do MAX(start_date).
How could I do that?
Thank you.
--From: pgsql-sql-owner+M68182-176663@lists.postgresql.org
--To: jj08@drivehq.com,pgsql-sql@lists.postgresql.org,janis@puris.lv
--Date: 9/6/2019 7:35:30 AM --Subject: RE:Re: A complex SQL query
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 Would something like this work for you ? http://www.sqlfiddle.com/#!17/2e45eb/9 select user_id, max(start_date) as start_date, case when max(end_date) < max(start_date) then null else max(end_date) end as end_date</div> from employment where employer = 'Micro' group by user_id ; On 6 Sep 2019, 14:31 +0200, jj08
-------------------------
Online Storage & Sharing, Online Backup, FTP / Email Server Hosting and More.
Drive Headquarters. Top quality services designed for business! Sign up free at: www.DriveHQ.com.
-------------------------
Online Storage & Sharing, Online Backup, FTP / Email Server Hosting and More.
Drive Headquarters. Top quality services designed for business! Sign up free at: www.DriveHQ.com
. =
view thread (8+ messages) latest in thread
Message-ID: <2260908401000000009736706@www>
Permalink: ../2260908401000000009736706@www/
Also on: postgresql.org/message-id/2260908401000000009736706@www
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: jj08@drivehq.com, pgsql-sql@lists.postgresql.org, pgsql-sql-owner+M68182-176663@lists.postgresql.org, janis@puris.lv
Subject: RE:RE:Re: A complex SQL query
In-Reply-To: <2260908401000000009736706@www>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox