1.wm_concat()函数是oracle内部用户下的函数，通常不建议使用，而listagg()函数只在oracle11g下才有，这时候就需要自定义合并列的聚集函数，具体sql如下：

CREATE OR REPLACE TYPE T_LINK AS OBJECT
(
  STR VARCHAR2(32767),STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT T_LINK) RETURN NUMBER,MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF  IN OUT T_LINK,VALUE IN VARCHAR2) RETURN NUMBER,MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF        IN T_LINK,RETURNVALUE OUT CLOB,FLAGS       IN NUMBER)
    RETURN NUMBER,MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT T_LINK,CTX2 IN T_LINK) RETURN NUMBER
)
/
CREATE OR REPLACE TYPE BODY T_LINK IS
  STATIC FUNCTION ODCIAGGREGATEINITIALIZE(SCTX IN OUT T_LINK) RETURN NUMBER IS
  BEGIN
    SCTX := T_LINK(NULL);
    RETURN ODCICONST.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAGGREGATEITERATE(SELF  IN OUT T_LINK,VALUE IN VARCHAR2) RETURN NUMBER IS
  BEGIN
    SELF.STR := SELF.STR || VALUE || ',';
    RETURN ODCICONST.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAGGREGATETERMINATE(SELF        IN T_LINK,FLAGS       IN NUMBER) RETURN NUMBER IS
  BEGIN
    RETURNVALUE := SUBSTR(SELF.STR,1,LENGTH(SELF.STR) - 1);
    RETURN ODCICONST.SUCCESS;
  END;

  MEMBER FUNCTION ODCIAGGREGATEMERGE(SELF IN OUT T_LINK,CTX2 IN T_LINK) RETURN NUMBER IS
  BEGIN
    NULL;
    RETURN ODCICONST.SUCCESS;
  END;
END;
/



CREATE OR REPLACE FUNCTION F_LINKS(P_STR VARCHAR2) RETURN CLOB
  AGGREGATE USING T_LINK;
/

把这段sql在oracle中运行一下，就可以使用了，具体使用示例如下：

select F_LINKS(t.name)
  from PHY_DEVICE_TBL t
 where instr(c.deviceid,to_char(t.id)) > 0

合并的结果列之间是用逗号分隔的！