DECLARE
  v_nameid NUMBER := -1; 
  v_categoryall VARCHAR2(4000);
BEGIN
  FOR r IN (SELECT nameid, category FROM table2 ORDER BY nameid, category)
  LOOP
    IF r.nameid != v_nameid THEN
      IF v_nameid != -1 THEN
        INSERT INTO table1(nameid, categoryall)
          VALUES (v_nameid,v_categoryall);
      END IF;
      v_nameid := r.nameid;
      v_categoryall := r.category;
    ELSE
      v_categoryall := v_categoryall||','||r.category;
    END IF;
  END LOOP;
  /* Catch the last record */
  IF v_nameid != -1 THEN
    INSERT INTO table1(nameid, categoryall)
      VALUES (v_nameid,v_categoryall);
  END IF;
END;