rides-today-without-riders.sql

-- Get all of today's rides that have no riders
SELECT r.id from Ride r
  LEFT OUTER JOIN (
    SELECT rideId, CAST(count(*) as UNSIGNED) cnt
    FROM UsersOnRides
    GROUP BY rideId
  ) ur ON ur.rideId = r.id
  where DATE_FORMAT(r.date,'%d/%m/%Y') = DATE_FORMAT(NOW(),'%d/%m/%Y')
	and COALESCE(ur.cnt,0) = 0;