mysql> select from_unixtime(time_received,'%m%d') as md,count(*) from ss_rt_feed where time_dispatched-time_received>3600 group by md;
+------+----------+
| md   | count(*) |
+------+----------+
| 0529 |   435346 |
| 0530 |   439425 |
| 0531 |   643918 |
| 0601 |   917178 |
| 0602 |  1843582 |
| 0603 |  1783357 |
| 0604 |   364779 |
| 0605 |    25345 |
| 0606 |   473562 |
| 0607 |   934715 |
| 0608 |  1419013 |
| 0609 |   619971 |
| 0610 |   152476 |
| 0611 |   480124 |
| 0612 |   274650 |
| 0613 |      736 |
| 0615 |        2 |
| 0616 |      854 |
| 0617 |        1 |
| 0618 |        2 |
| 0619 |       22 |
| 0620 |       21 |
| 0621 |      211 |
| 0622 |      357 |
| 0623 |        1 |
| 0624 |     9946 |
| 0626 |        3 |
| 0627 |      221 |
| 0628 |      788 |
+------+----------+
29 rows in set