WM_CONCAT 函數的用法

WM_CONCAT 函數的用法

select t.rank, t.Name from t_menu_item t;
<wbr><wbr><wbr> 10 CLARK<br><wbr><wbr><wbr> 10 KING<br><wbr><wbr><wbr> 10 MILLER<br><wbr><wbr><wbr> 20 ADAMS<br><wbr><wbr><wbr> 20 FORD<br><wbr><wbr><wbr> 20 JONES<br><wbr><wbr><wbr> 20 SCOTT<br><wbr><wbr><wbr> 20 SMITH<br><wbr><wbr><wbr> 30 ALLEN<br><wbr><wbr><wbr> 30 BLAKE<br><wbr><wbr><wbr> 30 JAMES<br><wbr><wbr><wbr> 30 MARTIN<br><wbr><wbr><wbr> 30 TURNER<br><wbr><wbr><wbr> 30 WARD<br> --------------------------------<br> 我们通过 10g 所提供的 WMSYS.WM_CONCAT 函数即可以完成 行转列的效果<br><wbr><wbr><wbr>select t.rank, WMSYS.WM_CONCAT(t.Name) TIME From t_menu_item t GROUP BY t.rank;<br> DEPTNO ENAME<br> ------ ----------<br><wbr><wbr><wbr> 10 CLARK, KING, MILLER<br><wbr><wbr><wbr> 20 ADAMS, FORD, JONES, SCOTT, SMITH<br><wbr><wbr><wbr> 30 ALLEN, BLAKE, JAMES, MARTIN, TURNER, WARD</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

例子如下：

SQL> create table idtable (id number,name varchar2(30));

Table created

SQL> insert into idtable values(10,'ab');

1 row inserted

SQL> insert into idtable values(10,'bc');

1 row inserted

SQL> insert into idtable values(10,'cd');

1 row inserted

SQL> insert into idtable values(20,'hi');

1 row inserted

SQL> insert into idtable values(20,'ij');

1 row inserted
SQL> insert into idtable values(20,'mn');

1 row inserted

SQL> select * from idtable;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- ------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 bc<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ij<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

6 rows selected
SQL> select id,wmsys.wm_concat(name) name from idtable
2 group by id;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- --------------------------------------------------------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi,ij,mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

SQL> select id,wmsys.wm_concat(name) over (order by id) name from idtable;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- --------------------------------------------------------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi,ij,mn<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi,ij,mn<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi,ij,mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

6 rows selected

SQL> select id,wmsys.wm_concat(name) over (order by id,name) name from idtable;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- --------------------------------------------------------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi,ij<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ab,bc,cd,hi,ij,mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

6 rows selected

个人觉得这个用法比较有趣.

SQL> select id,wmsys.wm_concat(name) over (partition by id) name from idtable;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- --------------------------------------------------------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab,bc,cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi,ij,mn<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi,ij,mn<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi,ij,mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

6 rows selected

SQL> select id,wmsys.wm_concat(name) over (partition by id,name) name from idtable;

<wbr><wbr><wbr><wbr><wbr><wbr><wbr> ID NAME<br> ---------- --------------------------------------------------------------------------------<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 ab<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 bc<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 10 cd<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 hi<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 ij<br><wbr><wbr><wbr><wbr><wbr><wbr><wbr> 20 mn</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

6 rows selected