I have two tables – Table A and Table B

Table A
Value      Value2      Number
-------    ------      ------
AA          1          138
AB          2          234
AC          3          897
BA          4          274
BB          5          391
CA          4          994
CA          5          287

Table B
Value      Value2      Number
-------    ------      ------
AA          1          458
AB          2          434
AC          3          557
CA          4          564

I am joining Table A and Table B with respect to Value and Value2 column.

Select * from Table A TA 
join Table B TB
on TA.Value = TB.Value and TA.Value2 = TB.Value2

Table A and Table B does not have all the matching value , for example value column of Table A have BA and BB which is not matching in Table B value column , So I need to replace BA and BB with CA and join it.

I started writing the script but wrote a long script.

I used except to get all the value column from TABLE A not matching TABLE B , and put this into a temp table. Then loop and replace the BA / BB column with CA column. But I think there should be a easy steps than this which I struggle to find.
Any suggestions please.