WEEK

Returns an integer between 1 and 53 which represents the week of the year. The week starts with Sunday. The argument must be a date or a time stamp.

Example:

Using the PROJECT table, return the week that project ('PL2100') ended.

  SELECT WEEK(PRENDATE)
    FROM PROJECT
    WHERE PROJNO = 'PL2100'

Returns 38 when using the sample table.