Merging Overlapping Date Ranges

SELECT [S1].[Category]
	,[S1].[StartDate]
	,MIN([T1].[EndDate]) AS [EndDate]
FROM [dbo].[DateRanges] AS [S1]
INNER JOIN [dbo].[DateRanges] AS [T1]
	ON (
			[S1].[Category] = [T1].[Category]
			AND [S1].[StartDate] <= [T1].[EndDate]
			AND NOT EXISTS (
				SELECT 1
				FROM [dbo].[DateRanges] AS [T2]
				WHERE [T1].[Category] = [T2].[Category]
					AND [T1].[EndDate] >= [T2].[StartDate]
					AND [T1].[EndDate] < [T2].[EndDate]
				)
			)
WHERE NOT EXISTS (
		SELECT 1
		FROM [dbo].[DateRanges] AS [S2]
		WHERE [S1].[Category] = [S2].[Category]
			AND [S1].[StartDate] > [S2].[StartDate]
			AND [S1].[StartDate] <= [S2].[EndDate]
		)
GROUP BY [S1].[Category]
	,[S1].[StartDate];