SELECT TOP 50 * FROM [things] [post]

JOIN [things] [category] ON [category].[id] = [post].[parent_id]

WHERE [post].[type] = 'post'

AND [category].[type] = 'category' AND [category].[slug] = 'animal-pictures'

ORDER BY ([post].[child_count] / DATEDIFF('hh', [post].[created_date], GETUTCDATE()) DESC;