I'm using the following code:
SELECT * FROM table
WHERE Col IN (123,123,222,....)
Depending on the database engine you are using, there can be limits on the length of an instruction.
SQL Server has a very large limit:
ORACLE has a very easy to reach limit on the other side.
So, for large IN clauses, it's better to create a temp table, insert the values and do a JOIN. It works faster also.