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I'll readily admit I'm not too familiar with MySQL specifically, but personally, I would try to avoid listing all the primary key values in an ad-hoc query.

What I would **rather do** personally is to run a separate query to select the rows to update, and then include a condition that the rows to be updated are those that exist in that set of rows.

Something not entirely dissimilar to

    UPDATE example_table
    SET column_A = 1
    WHERE primary_key_column IN (
        SELECT primary_key_column
        FROM example_table
        WHERE <bunch of complex conditions>
    )

Of course, in this *particular* case, you could just as well stick the `WHERE` clause from the subquery in the `UPDATE` statement itself, but that gets somewhat more complex if the query to find the rows to update is more complex than a plain SELECT from the same table that you're updating; say, it's actually selecting from a different table, with its own joins, maybe a union or two, and so on.

If you need to use the same set of key values multiple times and the query to find them is non-trivial, stick them into a temporary table that you `SELECT` from (or join against) instead, and put all of that into a stored procedure.