The function module "DATE_COMPUTE_DAY" will return the day by 1...7 when you input date. If the date have day:

• Monday : System will return value = 1
• Tuesday : System will return value = 2
• Wednesday : System will return value = 3
• Thursday : System will return value = 4
• Friday : System will return value = 5
• Saturday : System will return value = 6
• Sunday : System will return value = 7

Example

    CALL FUNCTION ’DATE_COMPUTE_DAY’
      EXPORTING
        date          = l_date1
      IMPORTING
        DAY           = l_day.   "Return Value