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Re: how to remove a for-loop from programming language and put it into the query?

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> I'm probably misunderstanding the problem, but can't you just do:
> 
> SELECT
> 	diag_value
> FROM
> 	diagnose_logs
> WHERE
> 	ts <= '2009-12-25 23:59:59'
> AND
> 	hardware_id BETWEEN 1 AND 500
> ORDER BY
> 	ts DESC
> LIMIT 1

Hi Thom,

Yes, I think you misunderstood.

An example of a table:

hardware_id | ts                  | diag_value
          1 | 2009-12-25 14:00:00 | 43.5 (*)
          1 | 2009-12-26 15:00:00 | 43.6
          1 | 2009-12-24 13:00:00 | 43.7
          2 | 2009-12-24 15:00:00 | 43.8 (*)
          2 | 2009-12-24 14:00:00 | 43.9
          2 | 2009-12-24 14:16:00 | 43.9
          2 | 2009-12-27 14:00:00 | 44.0

I need to get the "most recent" value before "2009-12-25 23:59:59" from
every hardware_id.

For hardware_id=1, the value would be:
          1 | 2009-12-25 14:00:00 | 43.5
for hardware_id=2, the value would be:
          2 | 2009-12-24 15:00:00 | 43.8

I need a query that will return me those lines marked with (*) :-) is
this possible?

Thanks!


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