Highest Peak and Longest River by Country

SELECT TOP(5)
    c.[CountryName],
    MAX(p.[Elevation]) AS [HighestPeakElevation],
    MAX(r.[Length]) AS [LongestRiverLength]
FROM [Countries] c
LEFT JOIN [MountainsCountries] mc ON c.[CountryCode] = mc.[CountryCode]
LEFT JOIN [Mountains] m ON mc.[MountainId] = m.Id
LEFT JOIN [Peaks] p ON m.[Id] = p.[MountainId]
LEFT JOIN [CountriesRivers] cr ON c.[CountryCode] = cr.[CountryCode]
LEFT JOIN [Rivers] r ON cr.[RiverId] = r.Id
GROUP BY c.[CountryName]
ORDER BY [HighestPeakElevation] DESC, [LongestRiverLength] DESC, c.[CountryName]