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MySQL 5.7 provides a number of ways to modify partitioned tables. It is possible to add, drop, redefine, merge, or split existing partitions. All of these actions can be carried out using the partitioning extensions to theALTER TABLE statement. There are also ways to obtain information about partitioned tables and partitions. We discuss these topics in the sections that follow.

To change a table's partitioning scheme, it is necessary only to use theALTER TABLE statement with apartition_options clause. This clause has the same syntax as that as used withCREATE TABLE for creating a partitioned table, and always begins with the keywordsPARTITION BY. Suppose that you have a table partitioned by range using the followingCREATE TABLE statement:

CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE)    PARTITION BY RANGE( YEAR(purchased) ) (        PARTITION p0 VALUES LESS THAN (1990),        PARTITION p1 VALUES LESS THAN (1995),        PARTITION p2 VALUES LESS THAN (2000),        PARTITION p3 VALUES LESS THAN (2005)    );

To repartition this table so that it is partitioned by key into two partitions using theid column value as the basis for the key, you can use this statement:

ALTER TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2;

This has the same effect on the structure of the table as dropping the table and re-creating it usingCREATE TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2;.

ALTER TABLE ... ENGINE = ... changes only the storage engine used by the table, and leaves the table's partitioning scheme intact. UseALTER TABLE ... REMOVE PARTITIONING to remove a table's partitioning. SeeSection 13.1.8, “ALTER TABLE Statement”.

In MySQL 5.7, it is possible to delete all rows from one or more selected partitions usingALTER TABLE ... TRUNCATE PARTITION.