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 a table and then inserting the numbers into a column added to the table using temporary tables.
ALTER SEQUENCE ORG_SEQ RESTART DECLARE GLOBAL TEMPORARY TABLE TEMP_ORG AS (SELECT NEXT VALUE FOR ORG_SEQ, ORG.* FROM ORG) WITH DATA
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
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