Both in terms of results produced and performance?
Code:
SELECT	 sab_stuc AS StudentID
	   , sab_seq2 AS SequenceNo
	   , (SELECT raa_name FROM srs_raa WHERE raa_code=sab_raac) AS RecordReason
	   , sab_begd AS [Date]
	   , sab_udf1 AS AMPM 
FROM srs_sab


SELECT	 sab_stuc AS StudentID
	   , sab_seq2 AS SequenceNo
	   , srs_raa.raa_name  AS RecordReason
	   , sab_begd AS [Date]
	   , sab_udf1 AS AMPM 
FROM srs_sab
INNER JOIN srs_raa ON raa_code=sab_raac