WEEKDAY Function

The WEEKDAY function accepts a DATE or DATETIME argument, and returns an integer in the range from 0 to 6 that represents the day of the week.

As the return value, zero (0) represents Sunday, one (1) represents Monday, and so on.

The following query returns all the orders that were paid on the same day of the week as the current date:
SELECT * FROM orders
   WHERE WEEKDAY(paid_date) = WEEKDAY(CURRENT);