Oracle glossary: in, not in

In and not in are conditions. Useful for tests one or more values for
membership(or not) in a list of values or subquery
Some example:
select * from table where col1 in (23, 45, 342) — where values of col1
match with 23, 45, 342
select * from table where col1 not in (23, 45, 342) — where values of col1
not match with 23, 45, 342
select * from table where (col1, col2) in (select val_a, val_b from
testtab) — where value of col1 and col2 match with val_a and val_b of
qubquery