This might help you

; WITH PRODUCT1 AS

(

SELECT*, DENSE_RANK() OVER( ORDER BY P.PARENT ) AS RN, 1 AS Lvl

FROMPRDST AS P

WHEREP.PARENT IN ( 1055874, 1055872 )

UNION ALL

SELECTPR.*, PR1.RN, PR1.Lvl + 1

FROMPRDST AS PR

INNER JOIN PRODUCT1 AS PR1 ON PR.PARENT = PR1.CHILD

)

SELECTPARENT, CHILD, CHILDQTY, POSNO

FROMPRODUCT1

ORDER BY RN, Lvl, PARENT