how to drop partition without dropping data in MySQL?

Question

I have a table like:

create table registrations(  id int not null auto_increment primary key, name varchar(50), mobile_number varchar(13))  engine=innodb  partition by range(id) ( partition p0 values less than (10000), partition p0 values less than (20000), partition p0 values less than max value); 

Not exactly like above but similar to that....

Now assume that my table has 200000 rows and now I want to remove partitions on the table and reorganize them in accordance to requirement without MAX VALUE in it.

Can any one help me to rearrange partition without dropping data or dropping table and recreating it ?

Answer 1

ALTER TABLE tbl REMOVE PARTITIONING; 

Answer 2

You can reorganize the partition p0 using the ALTER TABLE .. REORGANIZE PARTITION command.

http://dev.mysql.com/doc/refman/5.5/en/partitioning-management-range-list.html

If you intend to change the partitioning of a table without losing data, use ALTER TABLE ... REORGANIZE PARTITION

ALTER TABLE registrations  REORGANIZE PARTITION p0 INTO (     PARTITION p0 VALUES LESS THAN (10000),     PARTITION p0 VALUES LESS THAN (20000) ); 

Note that this will not make sense until you actually create several partitions e.g.

ALTER TABLE registrations  REORGANIZE PARTITION p0 INTO (     PARTITION p0 VALUES LESS THAN (10000),     PARTITION p1 VALUES LESS THAN (20000),     PARTITION p2 VALUES LESS THAN MAXVALUE ); 

Have a look at RANGE partitioning in MySQL

If your partition p2 is becoming too large you can split it the same way.