asked on

Ordering Query of Query by Date

I'm trying to aggregate 3 RSS feeds and order them by date, like you do. I've collected them with CFFEED and combined them as follows:

<cfquery name="qAllFeeds" dbtype="query">
	SELECT DC_DATE, TITLE, CONTENT, RSSLINK FROM feedquery1
	UNION
	SELECT DC_DATE, TITLE, CONTENT, RSSLINK FROM feedquery2
	UNION
	SELECT DC_DATE, TITLE, CONTENT, RSSLINK FROM feedquery3
	ORDER BY DC_DATE DESC
</cfquery>

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The DC_DATE column is formatted like "Wed, 13 Nov 2013 19:55:00 GMT" which, I didn't realize, is treated like a string in QoQ so everything ends up ordered by day name. I did some Googling and found the suggestion to use CAST, so I modified the query to:

<cfquery name="qAllFeeds" dbtype="query">
	SELECT CAST(DC_DATE AS DATE), TITLE, CONTENT, RSSLINK FROM feedquery1
	UNION
	SELECT CAST(DC_DATE AS DATE), TITLE, CONTENT, RSSLINK FROM feedquery2
	UNION
	SELECT CAST(DC_DATE AS DATE), TITLE, CONTENT, RSSLINK FROM feedquery3
	ORDER BY DC_DATE DESC
</cfquery>

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Which results in a very unspecific error:

How can I get my feed ordered correctly? Thanks!

Chris Stanyon

If your date is always in that format, then you can use the STR_TO_DATE function

SELECT
   DATE(STR_TO_DATE(DC_DATE, '%a, %d %b %Y %T')) as newDate,
   TITLE,
   CONTENT,
   RSSLINK
FROM feedquery1

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You would then need to ORDER BY on newDate

Chris Stanyon

Just as an addition, the %d in the STR_TO_TIME function assumes your Day number will be 0 padded (01, 02, 03 etc). If it's not (1, 2, 3 etc) then change it to %e

_agx_

@ChrisStanyon - Yes that would probably work w/MySQL but they're using a special in-memory query specific to CF, which doesn't support those functions.

@SiobhanElara - What's the stack trace of the error? If you don't see one, wrap the query in a cftry/cfcatch and dump the error <cfdump var="#cfcatch#">

Also, what are the URL's of one the feeds so we can test them?

Chris Stanyon

Ahhh- Didn't realise that :(

_agx_

The tags (ie MySQL) threw me off at first too :) I only noticed it was a QoQ when I looked closer at the code.

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_agx_

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SiobhanElara

ASKER

Perfect, that was exactly the problem! I didn't realize an alias was required there. (For the record, it works in CF8 too.)

_agx_

Yeah, probably a quirk of QoQ's. I think it'd work w/o an alias in db query. Though ... you'd still need to add an alias anyway. Otherwise you wouldn't be able to access the "DC_DATE" column in CF ;-)