15. Faultiest model

SELECT TOP (1) WITH TIES
         dd.Name AS Model,
        dd.[Times Serviced] AS [Times Serviced],
        t.[Parts Total] AS [Parts Total]
        FROM (
        SELECT TOP 100 j.ModelId AS ModelId,
        m.Name AS Name,
        COUNT(*) AS [Times Serviced]
        FROM Jobs AS j
        LEFT JOIN Models AS m ON j.ModelId = m.ModelId
        GROUP BY j.ModelId, m.Name
        ORDER BY [Times Serviced]) AS dd
        JOIN (SELECT TOP 100
              j.ModelId,
              m.Name AS Name,
              COUNT(*) AS [Times Serviced] ,
              ISNULL(SUM(p.Price * op.Quantity), 0) AS [Parts Total]
              FROM Jobs AS j
               FULL JOIN Models AS m ON j.ModelId = m.ModelId
              FULL JOIN Orders AS o ON o.JobId = j.JobId
              FULL JOIN OrderParts AS op ON op.OrderId = o.OrderId
              FULL JOIN Parts AS p ON p.PartId = op.PartId
              GROUP BY j.ModelId, m.Name
              ORDER BY [Times Serviced] DESC)
         AS t ON dd.Name = t.Name
         ORDER BY [Times Serviced] DESC