I have these two tables:

SQL> SELECT * FROM TAB_A;
MYDATE        P4         D1      D2      P5      P6
--------- ---------- ---------- ----------- ----------- -----------
30-OCT-12    949,324  4,437,654  10,203,116  25,303,632  13,900,078


SQL> SELECT * FROM TAB_B;
MYDATE        P4         D1      D2      P5      P6
--------- ---------- ---------- ----------- ----------- -----------
30-OCT-12    937,796  4,388,477  10,091,811  25,028,402  13,755,882

I need to subtract their respective columns and store the results into a third table like so:

SQL> INSERT INTO TAB_C (MYDATE, P4) SELECT SYSDATE,A.P4-B.P4 FROM  TAB_A A,TAB_B B WHERE A.MYDATE=B.MYDATE;

SQL> SELECT * FROM TAB_C;
MYDATE        P4         D1      D2      P5      P6
--------- ---------- ---------- ----------- ----------- -----------
30-OCT-12     926,268

The result is wrong. Basic math: 949324-937796=11528. Numeric values are stored as number datatypes. What am I missing here?