Mysql - Update every x hours

[seb hughes]

On some sites some stats are only updated every hour. I was wondering how this is done, because the query still shows the data, but only gets updated every x hours, how is this done.

[effigy]

Timing events--such as imports/updates--is done with the OS: cron on Unix, and services on Windows.

[seb hughes]

The thing is for example, on youtube.com video views are update every hour, when you view a video, you see the plays, so it must be getting it from the database, but only change every hour. so it might be done with a cronjob, btu how do they get it to still display data btu not update for x hours.

[effigy]

Use SQL. The following will give you all records whose date_field entries are within the hour.

 

SELECT * FROM table WHERE date_field >= DATE_SUB(NOW(), INTERVAL 1 HOUR)

 

[seb hughes]

Use SQL. The following will give you all records whose date_field entries are within the hour.

 

SELECT * FROM table WHERE date_field >= DATE_SUB(NOW(), INTERVAL 1 HOUR)

 

 

would this work with any prevous entries, eg 3 days ago, or 4 hours ago?

[effigy]

Yes. See the stuff about INTERVAL under DATE_ADD here.

[bubblegum.anarchy]

I recently learnt from fenway that mysql 5.1 has an inbuilt event scheduler:

 

http://dev.mysql.com/doc/refman/5.1/en/events.html