在開發過程中經常碰到要實現按照某一字段，將其它欄位中不同的值連線後顯示到一行上的需求。本人總結了以下幾種方法，在實際開發中可以參考。
建立表結構，在oracle9i上。
create table temp
(deptno int,
ename varchar(20 byte),
*** varchar(20 byte),
age varchar(20 byte)
); insert into temp values(10,'aaa','f','18');
insert into temp values(10,'bbb','f','19');
insert into temp values(10,'ccc','f','20');
insert into temp values(20,'ddd','m','21');
insert into temp values(20,'eee','m','22');
insert into temp values(20,'fff','m','23');
insert into temp values(30,'hhh','x','24');
insert into temp values(30,'ggg','x','25');
insert into temp values(30,'yyy','x','26');
insert into temp values(30,'ttt','x','27');
commit;
第一種寫法：
select distinct first_value (deptno) over (partition by deptno order by lv desc) as deptno,
first_value (ename) over (partition by deptno order by lv desc) as ename
from (select deptno, sys_connect_by_path (ename, ' ') ename,
level lv from (select deptno, ename,
lag (ename, 1, null) over (partition by deptno order by ename) ename_1
from (select deptno, ename from temp))
connect by prior ename = ename_1
order by deptno)
結果如下：
10| aaa bbb ccc
20| ddd eee fff
30| ggg hhh ttt yyy
改進後可以增加一列如下：
select distinct first_value (deptno) over (partition by deptno order by lv desc) as deptno,
first_value (***) over (partition by *** order by lv desc) as ***,
first_value (ename) over (partition by deptno order by lv desc) as ename
from (select deptno, ***, sys_connect_by_path (ename, ' ') ename, level lv
from (select deptno, ename, ***,
lag (ename, 1, null) over (partition by deptno order by ename) ename_1
from (select deptno, ename, *** from temp))
connect by prior ename = ename_1
order by deptno)
結果如下：
10|f| aaa bbb ccc
20|m| ddd eee fff
30|x| ggg hhh ttt yyy
第二種寫法：
select deptno, sys_connect_by_path (ename, ' ') as ename, ***,
sys_connect_by_path (age, ' ') as age
from (select deptno, ename, ***, age, rank () over (order by deptno)
+ row_number () over (order by deptno) rn,
row_number () over (partition by deptno order by deptno) rm
from temp) a1
where a1.rowid in (select max (a2.rowid) from temp a2 where a2.deptno = a1.deptno)
start with rm = 1
connect by prior rn = rn - 1
結果如下：
10| aaa bbb ccc|f| 18 19 20
20| ddd eee fff|m| 21 22 23
30| hhh ggg yyy ttt|x| 24 25 26 27
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