rossking

I have a DB It gets records from a sensor every 5 min This is then displayed on a Chart When I request 4 Hrs I get 48 records x 12 Sensors, Not a issue When I request 12 Hrs I get 144 records x 12 Sensors, A little Slower but Still OK But as I start to request longer periods Like 7 Days I start getting larger and Larger data sets causing time out issues with the AJAX Calls (4-30MB per sensor downloads of data) When looking at 4 weeks I really cant see the fine detail so is there a way to request records from MYSQL that drops some records in between Kinda like the Step function in a For loop If I request a period that has 2048 records but only want 204 records is there a way to say give me From -> To dates Step 10 and only return every 10th Record in the data set Thanks