ORACLE 12C创建wm_concat函数，
0.首先使用dba用户登录数据库，并解锁wmsys用户
alter user wmsys account unlock;
1.用WMSYS用户登录，不知道密码可以修改其密码
alter user wmsys identified by 123456;
2.在wmsys下创建可用的wm_concat函数，直接执行以下语句
--定义类型
CREATE OR REPLACE TYPE WM_CONCAT_IMPL 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 ;
--创建完成，给其创建同义词及授权，以供其他用户能正常使用。
create public synonym WM_CONCAT_IMPL for wmsys.WM_CONCAT_IMPL;
create public synonym wm_concat for wmsys.wm_concat;
--授权
grant execute on WM_CONCAT_IMPL to public;
grant execute on wm_concat to public;