NOT IN clause in query takin too much time to execute

I have to filter out rows from a table say A (contains 开发者_如何学JAVAonly 1 column ) that are not present in table B (contains many columns).

Apart from the only column in table A there is no other column that I can use.

So I am currently using the NOT IN clause but it is taking too much time to execute.

No room for Joins due to single common column

Please suggest your views

NOT IN (as well as <> for example) cannot be optimized with B-Tree organized indexes. So unfortunately you cannot do anything with this issue.