Immediately exit a query if a condition is verified - response (13) by Terry_Fisher

You can use the EXISTS clause as follows:
 
SELECT *
FROM    a_really_big_table
WHERE EXISTS
           (SELECT day_of_week
                FROM sys_calendar.calendar
               WHERE day_of_week = 2 -- is it a Monday
               AND calendar_date = date -- check todays date
          )
;

Teradata will immiediately determine whether the subquery returns an empty result set, and if so, will not even attempt to execute the outer query.