These twotables are linkedby the fieldA (same name)
I would like to count thenumber of rows inthe table1, with column A does not matchwith tableBand dittoforthe table2,the number ofrows in the table2, with the column A does not matchwith thetable A
you can't count key-fields, in your case column "A". If you need this, create a surrogato key (my fav for this is using the autonumber() - function) and decide wich column A you want to keep. If you need to count both columns A, my suggestion for your code would be similar to this:
LOAD
autonumber(A,1) AS A_ID, // key field for linking the tables