Returns an integer between 1 and 53 that represents the week of the year. The week starts with Monday. Week 1 is the first week of the year to contain a Thursday, which is equivalent to the first week containing January 4. Thus, it is possible to have up to 3 days at the beginning of the year appear as the last week of the previous year or to have up to 3 days at the end of a year appear as the first week of the next year. The argument must be a date, a timestamp, or a valid character string representation of a date or timestamp.
Example:
Using the PROJECT table, return the week that project ('AD2100') ended.
SELECT WEEK_ISO(PRENDATE) FROM PROJECT WHERE PROJNO = 'AD3100'
Returns 5 when using the sample table.