The ALTER SEQUENCE statement can be used to change a sequence in any of these ways:
A possible reason for specifying RESTART without a numeric value would be to reset the sequence to the START WITH value. In this example, the goal is to generate the numbers from 1 up to the number of rows in the table and then inserting the numbers into a column added to the table using temporary tables. Another use would be to get results back where all the resulting rows are numbered:
ALTER SEQUENCE ORG_SEQ RESTART SELECT NEXT VALUE FOR ORG_SEQ, ORG.* FROM ORG
For more information, see ALTER SEQUENCE in the SQL Reference topic in the Information Center.