WEEKDAY( )
The WEEKDAY( ) operator returns a positive integer, corresponding to the day
of the week implied by its DATE or DATETIME operand.
WEEKDAY( ) accepts a DATETIME or DATE operand, and returns an integer in the
range 0 through 6. Here zero represents Sunday, 1 represents Monday, and so on.
References
DATE( )DAY( )MONTH( )YEAR( )