SQL inner join show only unique Drivers - sql

Question

Learning, be kind.
Right now, this statement is showing the drivers and the vehicle id's they have used for these trips. how do I make this show only which drivers have used more than one vehicle rather than a list of vehicle ID and which driver used it? (does that make sense?):
SELECT DISTINCT s.vehicleID, o.FirstName + ' ' + o.LastName AS Driver
FROM Operators AS o, Runs AS r, Schedules AS s JOIN Trips AS t
ON s.scheduleID = t.scheduleID
WHERE r.BidDate >= '09/01/2004' AND r.BidDate <= '09/30/2004'

Answer 1

SELECT COUNT(DISTINCT s.vehicleID) AS Count, o.FirstName + ' ' + o.LastName AS Driver
FROM Operators AS o
JOIN Runs AS r ON o.ID = r.OperatorID
JOIN Schedules AS s ON r.ScheduleID = s.ScheduleID
WHERE r.BidDate BETWEEN '09/01/2004' AND '09/30/2004'
GROUP BY o.FirstName + ' ' + o.LastName
HAVING COUNT(DISTINCT s.vehicleID) > 1

Answer 2

My best guess not knowing the foreign key field names in your tables
SELECT
o.FirstName + ' ' + o.LastName AS Driver,
COUNT(s.vehicleID) AS VehicleCount
FROM
Operators AS o
JOIN Runs AS r ON o.operatorID = r.operatorID
JOIN Schedules AS s ON r.runsID = s.runsID
WHERE
r.BidDate >= '09/01/2004'
AND r.BidDate <= '09/30/2004'
GROUP BY
o.FirstName + ' ' + o.LastName
HAVING
COUNT(s.vehicleID) > 1

Answer 3

I don't really know what's the purpose of each table , but assuming you have table (map_driver_To_vehicle) with :
driverId , vehicleID
which represents that
driverid 5 took vehicleId 1
driverid 2 took vehicleId 5
etc...
You can do :
select driverId , cnt=count(distinct vehicleID )
from map_driver_To_vehicle
group by driverid
having count(distinct vehicleID ) >1
nb : you said more then one vehicle. So I presume you mean different car and not used more then one - the same car.
Either way you can remove the distinct.

Answer 4

You can use GROUP BY clause:
SELECT o.FirstName + ' ' + o.LastName AS Driver, COUNT(s.vehicleID) NoOfVehicleUsed
FROM Operators AS o, Runs AS r, Schedules AS s JOIN Trips AS t
ON s.scheduleID = t.scheduleID
WHERE r.BidDate >= '09/01/2004' AND r.BidDate <= '09/30/2004'
GROUP BY o.FirstName + ' ' + o.LastName
HAVING COUNT(s.vehicleID) > 1