Postgresql sql query - selecting rows outside a join

Hi all,

I am trying to do a query that returns  all rows that are _not_ part of
a join, and so far I cannot seem to find a query that doesn't take 30
minutes or more to run.

The basic query is "select * from tableA where tableA_id NOT IN (select
tableA_id from tableB)".

Is there a more efficient way of doing this?

Regards,
Graham
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