/**创建测试的表T1 也就是楼主说的A表**/
CREATE TABLE t1(
  ID VARCHAR2(10),
  pid VARCHAR2(10)
);
/**创建测试的表T2 也就是楼主说的B表**/
CREATE TABLE t2(
  pid VARCHAR2(10),
  pnumber VARCHAR2(10)
);
/**插入T1的数据,插入T2的测试数据**/
INSERT INTO t1 VALUES('A1','1');
INSERT INTO t1 VALUES('A2','2');
INSERT INTO t1 VALUES('A3','3');
INSERT INTO t2 VALUES('1','2');
INSERT INTO t2 VALUES('2','3');
INSERT INTO t2 VALUES('3','5');

/**解决方法的核心是:产生出1-10的一个列,作为“辅助列”**/
[color=#FF0000]SELECT LEVEL l FROM dual CONNECT BY LEVEL<=10;[/color]
/**最终的SQL**/
SELECT T1.ID, 'A1-'||T3.DZ AS LIST
  FROM T1, T2, (SELECT LEVEL DZ FROM DUAL CONNECT BY LEVEL <= 10) T3
 WHERE T1.PID = T2.PID
   AND T3.DZ <= T2.PNUMBER
   ORDER BY 1,2;