In MS ACCESS I currently find out a situation where I have to control / ommit the null value and nothing seems to be working, like I have tables with name "users", "player", users have a forieng key of "player" mean p_id.
I have entered admin record which is not player or etc. so its p_id should be null.
Now next what is happening, I have to registered user as player if he/she is not, and in the registration form I need only those users who are not registered means whoes p_id in users table is not equal to the p_id of player table.
And here what the problem occur it do fetch the record but duplicate records are fetched and even if I use explicit or group by clause, it is not resolved.
can you help me, what query I should use I am still working on it.