Inner Join Two Table, agrégation de champs varchar

Si vous avez Oracle 11g, vous pouvez utiliser la fonction LISTAGG, comme ceci :

Insert into    NEW_TFIDF_TABLE
SELECT T.ID, T.TERMS ||', '|| LISTAGG(TT.TERMS, ',') 
FROM TFIDF_TABLE T
INNER JOIN TERMS_TABLE TT  ON  T.ID=TT.ID
GROUP BY t.ID, t.TERMS /* assuming the id is unique in t */

Si vous utilisez une version antérieure, vous pouvez créer vos propres fonctions d'agrégation à l'aide d'un package. J'ai construit cette fonction FNC_CONCATCOMMASEPARATED, que j'utilise fréquemment moi-même.

CREATE OR REPLACE TYPE "AT_CONCATCOMMASEPARATED" as object
(
  V_CONCAT varchar2(32767), -- concatenated strings

  static function ODCIAggregateInitialize(
    P_CONTEXT in out AT_CONCATCOMMASEPARATED)
  return number,

  member function ODCIAggregateIterate(
    self  in out AT_CONCATCOMMASEPARATED,
    P_VALUE in     varchar2)
  return number,

  member function ODCIAggregateTerminate(
    self     in  AT_CONCATCOMMASEPARATED,
    P_RESULT out varchar2,
    P_FLAGS  in  number)
  return number,

  member function ODCIAggregateMerge(
    self      in out AT_CONCATCOMMASEPARATED,
    P_CONTEXT in     AT_CONCATCOMMASEPARATED)
  return number
);

create or replace type body AT_CONCATCOMMASEPARATED is

static function ODCIAggregateInitialize(
  P_CONTEXT in out AT_CONCATCOMMASEPARATED)
return number
is
begin
  if P_CONTEXT is null then
    P_CONTEXT := AT_CONCATCOMMASEPARATED('');
  else
    P_CONTEXT.V_CONCAT := null;
  end if;

  return ODCIConst.Success;
end;

member function ODCIAggregateIterate(
  self    in out AT_CONCATCOMMASEPARATED,
  P_VALUE in     varchar2)
return number
is
begin
  if self.V_CONCAT is null then
    self.V_CONCAT := P_VALUE;
  else
    self.V_CONCAT := self.V_CONCAT || ', ' || P_VALUE;
  end if;

  return ODCIConst.Success;
end;

member function ODCIAggregateTerminate(
  self     in  AT_CONCATCOMMASEPARATED,
  P_RESULT out varchar2,
  P_FLAGS  in  number)
return number
is
begin
  P_RESULT := substr(self.V_CONCAT, 0, 4000);

  return ODCIConst.Success;
end;

member function ODCIAggregateMerge(
  self      in out AT_CONCATCOMMASEPARATED,
  P_CONTEXT in     AT_CONCATCOMMASEPARATED)
return number
is
begin
  if P_CONTEXT.V_CONCAT is not null then
    if self.V_CONCAT is null then
      self.V_CONCAT := P_CONTEXT.V_CONCAT;
    else
      self.V_CONCAT := self.V_CONCAT || ', ' || P_CONTEXT.V_CONCAT;
    end if;
  end if;

  return ODCIConst.Success;
end;

end;

create or replace function FNC_CONCATCOMMASEPARATED (input varchar2) return varchar2
aggregate using AT_CONCATCOMMASEPARATED;

L'instruction d'insertion devient alors :

Insert into    NEW_TFIDF_TABLE
SELECT T.ID, T.TERMS ||', '|| FNC_CONCATCOMMASEPARATED(TT.TERMS) 
FROM TFIDF_TABLE T
INNER JOIN TERMS_TABLE TT  ON  T.ID=TT.ID
GROUP BY t.ID, t.TERMS /* assuming the id is unique in t */