Oracle 将多列合并成一列



对于下述表
create table reservation(
reid varchar2(55) not null,
rid varchar2(5),
gid number(18),
rtype varchar2(9),
retime date,
reduration number(1),
gpno number(11);
gname varchar2(12);
constraint pk_reid primary key(reid),
constraint fk_rid_reservation foreign key(rid) references room(rid)
);
要将reid、gid、gname合并成一列
select reid||'/'||gid||'/'||gname from reservation;字段间用/隔开