DB2树形结构层次设计和查询求助答:create table test2(id varchar(10),name varchar(20),pid varchar(10));insert into test2 values('1','A',null);insert into test2 values('101','B','1');insert into test2 values('10101','C','101');insert into test2 values('1010101','D','10101');insert into test2 values...