What will be output for this query:
CREATE PROC MyProc_p
(@param VARCHAR(30))
AS
SELECT @param AS Passed_param
GO
EXEC MyProc_p test_string
GO
EXEC MyProc_p 'test_string'
GO
EXEC MyProc_p test string
GO
EXEC MyProc_p 'test string'
GO
EXEC MyProc_p [test string]
GO