WEEKDAY(date)
Example
SELECT WEEKDAY('2016-09-21')
Output is 2
SELECT WEEKDAY(CURDATE())
This will return weekday in number of present ( today's ) date.
For a invalid date we will get Null as output
SELECT WEEKDAY('2015-02-31')
Output is NULL
SELECT WEEKDAY(CURDATE()- INTERVAL 1 DAY) as yesterday,
WEEKDAY(CURDATE()) as today,
WEEKDAY(CURDATE()+ INTERVAL 1 DAY) as tomorrow;