why explain partition shows first partition in every select query?

[Aamir Sohail]

Hii,

I have a table named edr on mysql 5.1.6* version. I have partitioned the table using alter -

ALTER TABLE edr PARTITION BY RANGE (TO_DAYS(eventDate))
(
PARTITION apr25 VALUES LESS THAN (TO_DAYS('2014-04-26')),
PARTITION apr26_30 VALUES LESS THAN (TO_DAYS('2014-05-01')),
PARTITION may01_05 VALUES LESS THAN (TO_DAYS('2014-05-06')),
PARTITION may06_10 VALUES LESS THAN (TO_DAYS('2014-05-11')),
PARTITION may11_15 VALUES LESS THAN (TO_DAYS('2014-05-16')),
PARTITION may16_20 VALUES LESS THAN (TO_DAYS('2014-05-21')),
PARTITION may21_25 VALUES LESS THAN (TO_DAYS('2014-05-26')),
PARTITION may26_31 VALUES LESS THAN (TO_DAYS('2014-06-01')),
PARTITION june01_05 VALUES LESS THAN (TO_DAYS('2014-06-06')),
PARTITION june06_10 VALUES LESS THAN (TO_DAYS('2014-06-11')),
PARTITION june11_15 VALUES LESS THAN (TO_DAYS('2014-06-16')));

now when I am running any query for example:

explain partitions select count(*) from edr where eventdate > '2014-05-21';

it gives me output for partitions as - apr25,may21_25, may26_31, jun01_05, jun_06_10, jun11_15.
Here in partition apr25 there is no record for such where condition.

please let me know is any thing wrong in above query or its a partition problem.