plsql: inserting Multiple rows from select and ignore duplicates - oracle

Question

I am using oracle 10g with TOAD.
I need to insert lacs of records using INSERT FROM SELECT.
BEGIN
INSERT INTO MYTABLE(C1,C2,C3)
SELECT C1,C2,C3 FROM MYTABLE2 WHERE C1>100;
EXCEPTION
WHEN DUP_VAL_ON_INDEX THEN NULL;
COMMIT;
END;
Here, the problem , i am facing is , if this select queries return rows which is already exists in MYTABLE, THEN all transaction will be rolledback.
Is there a way to insert all non-existent rows ,ignoring duplicate rows and continuing with insertion of non-existent rows and then committing the transaction?

Answer 1

Use the Distinct Keyword
BEGIN
INSERT INTO MYTABLE(C1,C2,C3)
SELECT distinct C1,C2,C3 FROM MYTABLE2 WHERE C1>100;
EXCEPTION
WHEN DUP_VAL_ON_INDEX THEN NULL;
COMMIT;
END;

Answer 2

Instead of trying to handle the exception, you can avoid these rows in the first place, e.g., by using the minus operator:
INSERT INTO mytable (c1, c2, c3)
SELECT c1, c2, c3
FROM mytable2
WHERE c1 > 100;
MINUS
SELECT c1, c2, c3
FROM mytable
WHERE c1 > 100 -- not necessary, but should improve performance

Answer 3

There are many ways to do it. First of all, you can try something like this:
insert into mytable(c1, c2, c3)
select distinct c1, c2, c3 from mytable2 where c1 > 100
minus
select c1, c2, c3 from mytable;
Otherwise, you can use something like
insert into mytable(c1, c2, c3)
select c1, c2, c3 from mytable2 where c1 > 100
log errors into myerrtable reject limit unlimited;
And so on...
More detailed about error logging. Feauture introduced since 10g release 2.
SQL> create table garbage(id integer);
Table created
SQL> insert into garbage select rownum from dual connect by level <= 10;
10 rows inserted
SQL> insert into garbage values (3);
1 row inserted
SQL> insert into garbage values (5);
1 row inserted
SQL> create table uniq(id integer not null primary key);
Table created
SQL> insert into uniq select * from garbage;
ORA-00001: unique constraint (TEST.SYS_C0010568) violated
SQL> select count(*) from uniq;
COUNT(*)
----------
0
SQL> exec dbms_errlog.create_error_log('uniq', 'uniq_err');
PL/SQL procedure successfully completed
SQL> insert into uniq select * from garbage
2 log errors into uniq_err reject limit unlimited;
10 rows inserted
SQL> select * from uniq;
ID
---------------------------------------
1
2
3
4
5
6
7
8
9
10
10 rows selected
SQL> select ora_err_mesg$, id from uniq_err;
ORA_ERR_MESG$ ID
---------------------------------------------------------------------- --
ORA-00001: unique constraint (TEST.SYS_C0010568) violated 3
ORA-00001: unique constraint (TEST.SYS_C0010568) violated 5

Answer 4

Thought I would make this an answer, but it really depends on what your trying to achieve.
You can check to see if the data is already in table2 using:
INSERT INTO mytable2 (c1, c2, c3)
SELECT DISTINCT c1,c2,c3 FROM mytable t1
WHERE c1 > 100
AND NOT EXISTS
(select 1 from mytable2 t2 where t2.c1 = t1.c1 and t2.c2 = t1.c2 and t2.c3 = t1.c3);
or you can use a merge like this:
MERGE INTO mytable2 m2
USING (SELECT DISTINCT c1, c2, c3 FROM mytable) m1
ON (m1.c1 = m2.c1 and m1.c2 = m2.c2 and m1.c3 = m2.c3)
WHEN NOT MATCHED THEN INSERT (c1, c2, c3) VALUES (m1.c1, m1.c2, m1.c3)
where m1.c1 > 100;
In both examples, you will only insert unique rows into mytable2