Group by and insert

Question

drop table gtestz
create table gtestz(zip varchar2(9), tname varchar2(10));
insert into gtestz values ('11111','cnp');
insert into gtestz values('11111','onn');
insert into gtestz values('22222','cnp');
commit;
SELECT ZIP,COUNT(DISTINCT(TNAME))
FROM GTESTZ
GROUP BY ZIP     ;            
CREATE TABLE gtest_tar(zip varchar2(9), tname varchar2(10));
insert into gtest_tar ??On table gtestz, i am doing a unique tname check for each zip, goal is to insert only unique tnames per zip into gtest_tar
meaning, from below sql, select only those whose count = 1, and insert into gtest_tar(zip, tname), how do i do that ?
SELECT ZIP,COUNT(DISTINCT(TNAME))
FROM GTESTZ
GROUP BY ZIP ;
gtest_tar should have
zip tname
22222 cnp

Answer 1

Try this:
CREATE TABLE gtestz
   zip     VARCHAR2 (9),
   tname   VARCHAR2 (10)
INSERT INTO gtestz
     VALUES ('11111', 'cnp');
INSERT INTO gtestz
     VALUES ('11111', 'onn');
INSERT INTO gtestz
     VALUES ('22222', 'cnp');
COMMIT;
SELECT * FROM GTESTZ;
SELECT ZIP, tname
  FROM (SELECT ZIP,
               tname,
               ROW_NUMBER () OVER (PARTITION BY tname ORDER BY 1) rn
          FROM GTESTZ)
WHERE rn > 1;
CREATE TABLE gtest_tar
   zip     VARCHAR2 (9),
   tname   VARCHAR2 (10)
INSERT INTO gtest_tar
   SELECT ZIP, tname
     FROM (SELECT ZIP,
                  tname,
                  ROW_NUMBER () OVER (PARTITION BY tname ORDER BY 1) rn
             FROM GTESTZ)
    WHERE rn > 1;
SELECT * FROM gtest_tar