As already pointed out your logic is flawed

e.g. One interpretation of the flawed logic is to find all combinations of VALUEA in both tables where they do not match

SELECT TABLEAVALUEA,TABLEBVALUEA,TABLEBVALUE

FROM TABLEA

CROSS JOIN TABLEB

WHERE TABLEAVALUEA <> TABLEBVALUEA

To get a good answer you need to post DDL to create tables and populate them with sample data and what the expect output should look like