11gr2和12C上已经摒弃了wm_concat函数，当时我们很多程序员在程序中确使用了该函数，导致程序出现错误，为了减轻程序员修改程序的工作量，只有通过手工创建个wm_concat函数，来临时解决该问题，但是注意，即使创建了该函数，在使用的过程中，也需要用to_char(wm_concat())方式，才能完全替代之前的应用。
一.解锁wmsys用户
alter user wmsys account unlock;
二.创建包、包体和函数
以wmsys用户登录数据库，执行下面的命令
CREATE OR REPLACE TYPE WM_CONCAT_IMPL AS OBJECT -- AUTHID CURRENT_USER AS OBJECT ( CURR_STR VARCHAR2(32767), STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT WM_CONCAT_IMPL) RETURN NUMBER, MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT WM_CONCAT_IMPL, P1 IN VARCHAR2) RETURN NUMBER, MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN WM_CONCAT_IMPL, RETURNVALUE OUT VARCHAR2, FLAGS IN NUMBER) RETURN NUMBER, MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT WM_CONCAT_IMPL, SCTX2 IN WM_CONCAT_IMPL) RETURN NUMBER ); / --定义类型body: CREATE OR REPLACE TYPE BODY WM_CONCAT_IMPL IS STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT WM_CONCAT_IMPL) RETURN NUMBER IS BEGIN SCTX := WM_CONCAT_IMPL(NULL) ; RETURN ODCICONST.SUCCESS; END; MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF IN OUT WM_CONCAT_IMPL, P1 IN VARCHAR2) RETURN NUMBER IS BEGIN IF(CURR_STR IS NOT NULL) THEN CURR_STR := CURR_STR || ‘,‘ || P1; ELSE CURR_STR := P1; END IF; RETURN ODCICONST.SUCCESS; END; MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF IN WM_CONCAT_IMPL, RETURNVALUE OUT VARCHAR2, FLAGS IN NUMBER) RETURN NUMBER IS BEGIN RETURNVALUE := CURR_STR ; RETURN ODCICONST.SUCCESS; END; MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT WM_CONCAT_IMPL, SCTX2 IN WM_CONCAT_IMPL) RETURN NUMBER IS BEGIN IF(SCTX2.CURR_STR IS NOT NULL) THEN SELF.CURR_STR := SELF.CURR_STR || ‘,‘ || SCTX2.CURR_STR ; END IF; RETURN ODCICONST.SUCCESS; END; END; / --自定义行变列函数: CREATE OR REPLACE FUNCTION wm_concat(P1 VARCHAR2) RETURN VARCHAR2 AGGREGATE USING WM_CONCAT_IMPL ; /
三.创建同义词并授权
create public synonym WM_CONCAT_IMPL for wmsys.WM_CONCAT_IMPL; create public synonym wm_concat for wmsys.wm_concat; grant execute on WM_CONCAT_IMPL to public; grant execute on wm_concat to public;
或者使用listagg函数
以下为类比方法
select deptno, listagg(ename,‘,‘) within group(order by ename) from scott.emp group by deptno DEPTNO PATH ---------- -------------------------------------------------------------------------------- 10 CLARK,KING,MILLER 20 ADAMS,FORD,JONES,SCOTT,SMITH 30 ALLEN,BLAKE,JAMES,MARTIN,TURNER,WARD select deptno,wm_concat(ename) as path from scott.emp group by deptno DEPTNO PATH ---------- -------------------------------------------------------------------------------- 10 CLARK,MILLER,KING 20 SMITH,FORD,ADAMS,SCOTT,JONES 30 ALLEN,JAMES,TURNER,BLAKE,MARTIN,WARD