insert into t1 (c1, c2, c3, c4 , c5, c6)
select t2.c1, t2.c2, t2.c3, t2.c4 , t2.c5 , sysdate from t2,t1
where t1.c1=t2.c1
and t1.c2=t2.c2
and t1.c3=t2.c3
and c1 || c2 < to_char(sysdate,'YYYYMM')
select t2.c1, t2.c2, t2.c3, t2.c4 , t2.c5 , sysdate from t2,t1
where t1.c1=t2.c1
and t1.c2=t2.c2
and t1.c3=t2.c3
and c1 || c2 < to_char(sysdate,'YYYYMM')
select t2.c1, t2.c2, t2.c3, t2.c4 , t2.c5 , sysdate from t2,t1
where t1.c1=t2.c1
and t1.c2=t2.c2
and t1.c3=t2.c3
and t2.c1 || t2.c2 < to_char(sysdate,'YYYYMM')
insert into t1 (c1, c2, c3, c4 , c5, c6)
(select c1, c2, c3, c4 , c5 , sysdate from t2where t2.c1 || t2.c2 < to_char(sysdate,'YYYYMM')minusselect t2.c1, t2.c2, t2.c3, t2.c4 , t2.c5 , sysdate from t2,t1
where t1.c1=t2.c1
and t1.c2=t2.c2
and t1.c3=t2.c3
and t2.c1 || t2.c2 < to_char(sysdate,'YYYYMM')
)