oracle wm_concat

CREATE OR REPLACE TYPE wm_concat_impl   AUTHID CURRENT_USERAS 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);CREATE OR REPLACE TYPE BODY wm_concat_implIS   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;CREATE OR REPLACE FUNCTION wm_concat (p1 VARCHAR2)   RETURN VARCHAR2   AGGREGATE USING wm_concat_impl;