Question

I have a mysql MyIsam table with a field datestamp (datetime), I am trying to return all records that have a datestamp within the last 3 hours, but group it into 10 chunks (so for this example group one would be the first 18 minutes etc…)

Any ideas? Is this possible in mysql?

Answer 1

I think this may work:

$t = date("U",strtotime("-3 Hours"));
$sql = "SELECT *, FLOOR((UNIX_TIMESTAMP(datestamp) - ".$t.") / 1080) as chunk 
    FROM table WHERE UNIX_TIMESTAMP(datestamp) > '".$t."' GROUP BY chunk";

Devide the difference with 1/10th of the 3 hour interval (1080 sec). This gives chunks 0,1,2…9, where 0 means the first 18 minutes.