A Little SQL Help

rubyonrails-talk
1

Can someone give me a hand with the sql (mysql works for me) for this rails project...

Data similar to this:

Station Status WKRP Pending WKRP Pending WKRP Deleted WIBC Deleted WFBQ Pending WFBQ Nutty

What I need is an sql statement that will count the various status states and return a *single row* for each station. Like:

Station Pending Deleted Nutty WKRP 2 1 0 WIBC 0 1 0 WFBQ 1 0 1

I can get the counts of each station/status in individual lines and loop through the array counting the various status states, but the runtime for that is growing and I'm looking for a better solution before it becomes a problem.

Ideas or suggestions?

2

SELECT station,         SUM(CASE WHEN status = 'Pending' THEN 1 ELSE 0 END) AS "Pending",         SUM(CASE WHEN status = 'Deleted' THEN 1 ELSE 0 END) AS "Deleted",         SUM(CASE WHEN status = 'Nutty' THEN 1 ELSE 0 END) AS "Nutty" FROM your_table GROUP BY station;

How does that work for you?

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

3

Thanks Rob, that's pretty good. Close to one of my attempts.

But what if status is not static? The distinct values of `status` change in value and quantity... which it does.

4

Thanks Rob, that's pretty good. Close to one of my attempts.

But what if status is not static? The distinct values of `status` change in value and quantity... which it does.

Then you can build the SQL after first getting the distinct values of the status.

Or do the analysis in ruby after getting the raw [station, status] data.

-Rob

SELECT station,         SUM(CASE WHEN status = 'Pending' THEN 1 ELSE 0 END) AS "Pending",         SUM(CASE WHEN status = 'Deleted' THEN 1 ELSE 0 END) AS "Deleted",         SUM(CASE WHEN status = 'Nutty' THEN 1 ELSE 0 END) AS "Nutty" FROM your_table GROUP BY station;

How does that work for you?

-Rob

Rob Biedenharn http://agileconsultingllc.com R...@AgileConsultingLLC.com

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Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

5

Ballin!