PL/SQL :: SQL For Table Transform

I need trasform information from table A to table B. Table A is refreshed every day, Table B needs record all the information, including records nolonger existing in TABLE A. I would like to use one SQL to complete the operation. The merge works only for insert and update, but not for delete.

Here are the structure of the tables:

Create TABLE A
(
course_number int;
course_txt varchar(20);
);

[Code]...

The record of tables will be as following:

On May 1, 2012
Table A.
100 math
200 english
500 social
Table B.
new 100 math May1, 2012
new 200 english May1, 2012
new 500 social May1, 2012

On May 2, 2012
Table A.
100 science
300 social

Table B.

update 100 science May2, 2012
delete 200 english May2, 2012
new 300 social May2, 2012
new 500 french May1, 2012