SQL Exercise Need Help to get answers

1-->List AVGcost, MINcost, MAXcost, and CNTcost for all repairs. Use AVG(), MAX(), MIN(), COUNT(*).

2-->List AVGcost, MINcost, MAXcost, and CNTcost for repairs for SupplierID 1518. Use AVG(), MAX(), MIN(), COUNT(*)

3-->List LastRepair for a repair that was supplied by SuplierID 1518. LastRepair is the last slRepair.RepairDate of a repair for a supplier

4-->List FirstRepair for a repair that was supplied by SupplierID 1504. FirstRepair is the first slRepair.RepairDate of a repair for a supplier

5-->List TripCnt for all trips where slTrip.WaterTemp is greater than 75 and the trip launched from slTrip.LaunchID 2 or 7 or 8.

6-->List MaxTripHour for all trips where slTrip.WaterTemp is less than 65 and the trip launched from slTrip.LaunchID 2. MaxTripHour is the maximum of slTrip.TripHour which is the duration of the trip in hours.

7-->How many maintenance items have NULL values for slMaintenance.MaintenanceCost? List NullCnt for all maintenance items where NullCnt is the number of rows having NULL for slMaintenance.MaintenanceCost.

8-->How many distinct captians have piloted a trip? List CaptainCnt for all distinct values of slTrip.CaptainID.

Hint -->SELECT COUNT(DISTINCT attribute) AS Alias

9-->How many suppliers have supplied items for repairs? List SuppCnt for all distinct values of slRepair.SupplierID.

Hint-SELECT COUNT(DISTINCT attribute) AS Alias

sIMaintenance sIRepair Column Nme Data Type MaintenancelD int Column N.. Data Type RepairlD int RepairDate datetime RepairCost float Description varchan(500) SupplierlD int ShiplD Column Nae Data Type slGasPurchase slShip slPax Column N... Data Type Column Ne Data Type PadD Column Name Data Type PurchaseDte datetime MgYear int int PaxLastName varchar200 Gellons Model int slTrip Column Name Data Type slLaunch TriplD slSupplier Column Name Data Type LaunchlD Column Name Data Type CensusD Column Name ata Type SupplierID int int varchan 100) PaND int TripEngineEnd float aterTemp int slWayPoint sIFloatPlan Column Name Data Type WayPointD nt WayPoint vachar(250) Column Name Data Type FloatPlanlD TriplD WayPointID