Example of DELETE - SQL

As with UPDATE, a FOR PORTION OF clause can be specified if the target table has a defined period name, as illustrated in Example.

Example: Deleting a "portion" of the salary history table

DELETE SAL_HISTORY

FOR PORTION OF During

FROM DATE ('2012-01-01') TO DATE ('2012-02-01')

WHERE EmpNo = '123456';

As a result, the row

('123456', 55000, DATE ('2011-09-01'), DATE ('2012-08-01'))

is replaced by the two rows

('123456', 55000, DATE ('2011-09-01'), DATE ('2012-01-01')),

('123456', 55000, DATE ('2012-02-01'), DATE ('2012-08-01'))

and the DELETE statement will have effected an increase in cardinality instead of the usual decrease.