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02.20.2008 at 07:28AM PST, ID: 23177833
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9.0

Select Distinct Query Issue

Asked by MrBaseball9 in MySQL Server, PHP and Databases

Tags:

This will probably be an easy question:

I have a table called link_status.  Inside this table I have fields (location_id, status, last_updated, last_changed)

Data is written to this table every 5 minutes, containing the same location_id's, but the status, last_updated, and last)changed) fields changed.

I'd like to have a query that selects the most recent entry for each location. I know that I need a distinct location_id, but the rest of the data changes so I can't use a SELECT DISTINCT statement.

Date Example
location_id          status          last_updated         last_changed
111                        0                (timestampNew)     (timestampNew)
222                        1                (timestampNew)     (timestampNew)
333                        0                (timestampNew)     (timestampNew)
111                        0                (timestamp)            (timestamp)
222                        1                (timestamp)            (timestamp)
333                        1                (timestamp)            (timestamp)

So in this case, I'd need to return the status' of 111, 222, & 333 where the last_updated field is the newest.Start Free Trial
[+][-]02.20.2008 at 07:34AM PST, ID: 20938738

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[+][-]02.20.2008 at 07:48AM PST, ID: 20938874

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[+][-]02.20.2008 at 07:51AM PST, ID: 20938909

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[+][-]02.20.2008 at 07:58AM PST, ID: 20938976

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[+][-]02.20.2008 at 07:59AM PST, ID: 20938993

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About this solution

Zones: MySQL Server, PHP and Databases
Tags: PHP MYSQL
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Solution Provided By: AdrianSRU
Participating Experts: 2
Solution Grade: A
 
 
[+][-]02.20.2008 at 08:12AM PST, ID: 20939117

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