删除2015-01-01 前的历史纪录

DELETE FROM  history WHERE clock < UNIX_TIMESTAMP(  '2015-01-01 00:00:00' );
DELETE FROM history_uint WHERE clock <  UNIX_TIMESTAMP(  '2015-01-01 00:00:00' );


或者使用时间戳

DELETE FROM  history WHERE clock < 1420041600;
DELETE FROM history_uint WHERE clock < 1420041600;