Help with complicated query (total SQL newb!)

From: britt_mcclafferty <brittany(dot)mcclafferty(at)gmail(dot)com>
To: pgsql-sql(at)postgresql(dot)org
Subject: Help with complicated query (total SQL newb!)
Date: 2015-12-16 22:06:54
Message-ID: 1450303614561-5877942.post@n5.nabble.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

Hi there,

I am only just learning SQL and have three specific questions on correct
syntax for my queries...

*1.* The 'Data1' and 'Data2' columns have stings which contain both numbers
and letters. In the query below I have removed the letters and re-named the
trimmed versions. I want to cast the remaining numbers to numerics and run
aggregate functions on them (ie AVG, MAX etc). However, whenever I wrap the
TRIM in a function I am getting errors. How do I fix this?

Here is my query

SELECT
data1,
TRIM(TRAILING ' total bookmarks' FROM data1) as Bookmarks_trim,
data2,
TRIM(TRAILING ' folders' FROM data2) as Folders_trim,
event_code,
user_id
FROM events
WHERE event_code =8

And this is what it returns: http://screencast.com/t/DCvey2sAxZ

*2. *I want to add an additional parameter to the query above to show only
DISTINCT instances of the user_id. The separate query I have for that is
below. How do I combine the two?

SELECT DISTINCT
*
FROM (SELECT DISTINCT user_id, event_code, data1, data2
FROM events) AS temp
WHERE event_code = 8

This returns: http://screencast.com/t/IXhpix0vLNSp

*3. *Lastly, I want to be able to sort by DESC on both the trimmed data1
column and data2 (to see the users with the highest number of folders and
bookmarks) I know you do this with ORDER BY but I am not sure where it would
go in such a large query.

ANY help would be hugely appreciated.

--
View this message in context: http://postgresql.nabble.com/Help-with-complicated-query-total-SQL-newb-tp5877942.html
Sent from the PostgreSQL - sql mailing list archive at Nabble.com.

Responses

Browse pgsql-sql by date

  From Date Subject
Next Message Adrian Klaver 2015-12-17 00:19:31 Re: Help with complicated query (total SQL newb!)
Previous Message David G. Johnston 2015-12-16 21:42:13 Re: cant get what I want from array_to_json (simple)