mysql datetime 字段的比较

SELECT * FROM `record_card` where unix_timestamp(rec_time) BETWEEN unix_timestamp('2015-9-14 14:03:45') and  unix_timestamp('2015-12-14 14:03:45') ;

between  一定要 从  小时间    到  大时间 

SELECT * FROM `record_card` where unix_timestamp(rec_time) = unix_timestamp('2015-10-14 14:03:45');