Example
timestamp
2012-09-25 00:00:00-->
2012-09-25 00:00:50
2012-09-25 00:01:23
2012-09-25 00:01:30-->
2012-09-25 00:02:33
2012-09-25 00:02:40
2012-09-25 00:03:01-->i want those

SELECT create_time
FROM timeTable
WHERE create_time
IN (

SELECT min( create_time )
FROM timeTable
GROUP BY FROM_UNIXTIME( UNIX_TIMESTAMP( create_time ) - MOD( UNIX_TIMESTAMP( create_time ) , 60 ) );

SELECT create_time
FROM timeTable
WHERE create_time
IN (

SELECT min( create_time )
FROM timeTable
GROUP BY DATE_FORMAT( `create_time` , 'Y-M-D %H:%i' )
);

SET @time := '1000-01-01 00:00:00';
SET @interval := 60;

SELECT colDate
FROM table
WHERE TIMESTAMPDIFF( SECOND, @time, colDate ) >= @interval
    AND @time := colDate