ORACLE 字符串聚合函数 strcat

create or replace type strcat_type as object

      (

        currentstr varchar2(4000),

        currentseprator varchar2(8),

        static function ODCIAggregateInitialize(sctx IN OUT strcat_type) return number,

        member function ODCIAggregateIterate(self IN OUT strcat_type,value IN VARCHAR2) return number,

        member function ODCIAggregateTerminate(self IN strcat_type,returnValue OUT VARCHAR2, flags IN number) return number,

        member function ODCIAggregateMerge(self IN OUT strcat_type,ctx2 IN strcat_type) return number

      );

 

/*------------------------------------------------------------------------------------------------------------------------------------------------*/

 

create or replace type body strcat_type is

      static function ODCIAggregateInitialize(sctx IN OUT strcat_type) return number is

      begin

        sctx := strcat_type('',',');

        return ODCIConst.Success;

      end;

      member function ODCIAggregateIterate(self IN OUT strcat_type, value IN VARCHAR2) return number is

      begin

        if self.currentstr is null then

           self.currentstr := value;

        else

          self.currentstr := self.currentstr ||currentseprator || value;

        end if;

        return ODCIConst.Success;

      end;

      member function ODCIAggregateTerminate(self IN strcat_type, returnValue OUT VARCHAR2, flags IN number) return number is

      begin

        returnValue := self.currentstr;

        return ODCIConst.Success;

      end;

      member function ODCIAggregateMerge(self IN OUT strcat_type, ctx2 IN strcat_type) return number is

      begin

        if ctx2.currentstr is null then

          self.currentstr := self.currentstr;

        elsif self.currentstr is null then

          self.currentstr := ctx2.currentstr;

        else

          self.currentstr := self.currentstr || currentseprator || ctx2.currentstr;

        end if;

        return ODCIConst.Success;

      end;

      end;

 

/*------------------------------------------------------------------------------------------------------------------------------------------------*/

 

CREATE OR REPLACE FUNCTION strcat (input VARCHAR2) RETURN VARCHAR2 PARALLEL_ENABLE AGGREGATE USING strcat_type;

 

转自：http://space.itpub.net/3090/viewspace-625084