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 |
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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.
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