Efficiently Removing Table Data
TRUNCATE statement to remove all data from a table:
SQL> truncate table emp;
If you don’t want the TRUNCATE statement to de-allocate the currently allocated extents, then use the REUSE STORAGE clause:
SQL> truncate table emp reuse storage;
TRUNCATE statement is often used when working with partitioned tables.
alter table f_sales truncate partition p_2012;