Splitting a partition involves dividing an existing partition into two. You can split a partition using the ALTER TABLE command. You can only split partitions at the lowest level of your partition hierarchy (only partitions that contain data can be split). The split value you specify will go into the latter partition.
For example, to split a monthly partition into two with the first partition containing dates January 1-15 and the second partition containing dates January 16-31:
ALTER TABLE sales SPLIT PARTITION FOR ('2008-01-01')
INTO (PARTITION jan081to15, PARTITION jan0816to31);
If your partition design has a default partition, you must split the default partition in order to add a new partition. You can only split default partitions at the lowest level of your partition hierarchy (only default partitions that contain data can be split).
When using the INTO clause, the second partition name specified should always be that of the existing default partition. For example, to split a default range partition to add a new monthly partition for January 2009:
ALTER TABLE sales SPLIT DEFAULT PARTITION
START ('2009-01-01') INCLUSIVE
END ('2009-02-01') EXCLUSIVE
INTO (PARTITION jan09, default partition);