WEEK(), WEEKOFYEAR() — Returns the week of the year as an integer value.
WEEK( timestamp-value )
WEEKOFYEAR( timestamp-value )
The WEEK() and WEEKOFYEAR() functions are synonyms and return an integer value between 1 and 52 representing the timestamp's week of the year. These functions produce the same result as using the WEEK_OF_YEAR keyword with the EXTRACT() fucntion.