MSSQL Format U.S. Phone Number

SELECT CASE LEN(phone)
		WHEN 11
			THEN LEFT(phone, 1) + STUFF(STUFF(STUFF(phone, 1, 1, ' ('), 6, 0, ') '), 11, 0, '-')
		WHEN 10
			THEN STUFF(STUFF(STUFF(phone, 1, 0, ' ('), 6, 0, ') '), 11, 0, '-')
		WHEN 7
			THEN STUFF(phone, 4, 0, '-')
		ELSE 'Invalid phone'
		END AS 'Formatted Phone'
FROM TABLE

If you have to sanitize your field first it gets ugly but is still possible

CASE LEN(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(phone, '.', ''), '-', ''), '(', ''), ')', ''), ' ', ''))
		WHEN 11
			THEN LEFT(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(phone, '.', ''), '-', ''), '(', ''), ')', ''), ' ', ''), 1) + STUFF(STUFF(STUFF(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(phone, '.', ''), '-', ''), '(', ''), ')', ''), ' ', ''), 1, 1, ' ('), 6, 0, ') '), 11, 0, '-')
		WHEN 10
			THEN STUFF(STUFF(STUFF(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(phone, '.', ''), '-', ''), '(', ''), ')', ''), ' ', ''), 1, 0, ' ('), 6, 0, ') '), 11, 0, '-')
		WHEN 7
			THEN STUFF(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(phone, '.', ''), '-', ''), '(', ''), ')', ''), ' ', ''), 4, 0, '-')
		ELSE 'Invalid phone'
		END AS Phone

Reference: http://www.sqlservercurry.com/2010/11/format-phone-numbers-in-sql-server.html