WITH t AS
(
SELECT 'DW001' col1, 'DL006' col2 FROM dual
UNION ALL SELECT 'DW002', 'DL007' FROM dual
UNION ALL SELECT 'DW003', 'DL003' FROM dual
UNION ALL SELECT 'DW004', 'DL004' FROM dual
UNION ALL SELECT 'DW005', 'DL003' FROM dual
UNION ALL SELECT 'DW006', 'DL005' FROM dual
UNION ALL SELECT 'DW007', 'DL001' FROM dual
UNION ALL SELECT 'DW008', 'DL002' FROM dual
UNION ALL SELECT 'DW009', 'DL005' FROM dual
)
SELECT *
  FROM t
 ORDER BY MIN(col1) OVER(PARTITION BY col2), col1
;