Quetions on Joins

Hi,

I have a query where I want to filter out records from table_a if a
field in table_a matches in table table_b. Basically table_b defines the
filter.

If table_b however is empty i dont get any results

SELECT A.value_one FROM table_a AS A, table_b AS B WHERE  A.value_two <>
B.value_two;
or
SELECT A.value_one FROM table_a AS A, table_b AS B WHERE  A.value_two <>
B.value_two AND B.value_two NOTNULL;

Only work if the there is a value in table_b.
Could anyone tell me if there is a way to do that ?


Thanks a lot
Alex

PS: I'd like to thank here persons who reply rather than sending the
message per mail.