Join selection with a unique-weight sort sequence table (SRTSEQ(*LANGIDUNQ) LANGID(ENU)).
SELECT * FROM STAFF S1, STAFF S2 WHERE S1.JOB = S2.JOB
or the same query using the JOIN syntax.
SELECT *
FROM STAFF S1 INNER JOIN STAFF S2
ON S1.JOB = S2.JOB
When using the OPNQRYF command, specify:
OPNQRYF FILE(STAFF STAFF) FORMAT(FORMAT1) JFLD((1/JOB 2/JOB *EQ)) SRTSEQ(*LANGIDUNQ) LANGID(ENU)
DB2 UDB for AS/400 could use either index HEXIX or index UNQIX for either query.