Compare two tables having different number of rows based on 2 columns

Question

Hi,
I am having two tables table a having field1, field2 and table b having fields field1 and field2.
I want those records from table a in which field1 of table a is not matching to field1 of table b and field2 of table b not matching to field2 of table b, but i also want the bifurcation of records as whether field 1 is not matching, field 2 is not matching or both fields 1 & 2 are not matching.
e.g.
table a table b
field1 field2 field1 field2
1 6 12 5
2 5 1 9
13 51 13 51
45 31 99 121
33 45
In this case my output should be
table a
field1 field2 Mtchng_Field
1 6 Field 2 not mtchng
2 5 Field 1 not mtchng
45 31 Feild1 and Field2 both not matching
How would i get my result in the required format.

Answer 1

sql>select * from t1;
N1 N2 
1   6 
2   5 
13  51 
45  31 
33  45 
sql>select * from t2;
N1 N2 
12  5 
1   9 
13  51 
99  121
sql>
select n1,n2,decode(nvl(p1,0)+nvl(p2,0),0,'No match',1,'F2 not match',2,'F1 not match','Match') status
from(
  select n1,n2,(select 1
               from t2 where n1=t1.n1) p1,(select 2
                                       from t2 where n2=t1.n2) p2
from t1);
N1 N2 STATUS 
1   6   F2 not match 
2   5   F1 not match 
13  51  Match 
45  31  No match 
33  45  No match
Message was edited by:
        jeneesh
Message was edited by:
        jeneesh
Some problems...