Oracle Query :
SELECT *
FROM (
SELECT client_id, priority, phone_number, phone_type
FROM client_table c
LEFT OUTER JOIN
phone_table p
ON ( c.phone_id = p.phone_id )
)
PIVOT ( MAX( phone_type ) AS phonetype, MAX( phone_number ) AS phonenumber
FOR priority IN ( 1 AS Prio1, 2 AS Prio2, 3 AS Prio3 ) );
Utdata :
CLIENT_ID PRIO1_PHONETYPE PRIO1_PHONENUMBER PRIO2_PHONETYPE PRIO2_PHONENUMBER PRIO3_PHONETYPE PRIO3_PHONENUMBER
---------- --------------- ----------------- --------------- ----------------- --------------- -----------------
1 C 9999999999 H 5555555555 W 7777777777