##查看要处理的分区的数据量，并导出作为备份

mysql> select count(*) from baby_account_change_log where updated_time >'2016-12-01 00:00:00' and updated_time <'2017-01-01 00:00:00';
+----------+
| count(*) |
+----------+
| 66252 | 
+----------+
1 row in set (0.23 sec)

##导出备份

mysql> select * into outfile '/tmp/baby_account_change_log_p1.sql' from baby_account_change_log where updated_time >'2016-12-01 00:00:00' and updated_time <'2017-01-01 00:00:00' limit 100000000000;
Query OK, 66252 rows affected (2.71 sec)


##确认要处理分区

mysql> explain partitions select count(*) from baby_account_change_log where updated_time >'2016-12-01 00:00:00' and updated_time <'2017-01-01 00:00:00';

+----+-------------+-------------------------------+------------+-------+---------------+---------+---------+------+-------+--------------------------+
| id | select_type | table       | partitions | type | possible_keys | key  | key_len | ref | rows | Extra     |
+----+-------------+-------------------------------+------------+-------+---------------+---------+---------+------+-------+--------------------------+
| 1 | SIMPLE  | baby_account_change_log | p1   | index | NULL   | PRIMARY | 8  | NULL | 66252 | Using where; Using index | 
+----+-------------+-------------------------------+------------+-------+---------------+---------+---------+------+-------+--------------------------+

##删除分区

mysql> alter table baby_account_change_log drop partition p0;
Query OK, 0 rows affected (0.01 sec)

#错误提示删除存储最大值分区
mysql> alter table baby_account_change_log add partition(PARTITION p13 VALUES LESS THAN (unix_timestamp('2017-12-31 23:59:59')));
ERROR 1481 (HY000): MAXVALUE can only be used in last partition definition

#删除存储最大值分区
mysql> alter table baby_account_change_log drop partition p12;

##增加新的分区

mysql> alter table baby_account_change_log add partition(PARTITION p12 VALUES LESS THAN (unix_timestamp('2017-12-31 23:59:59')));