$_query = 'UPDATE ' . TABLE_A1 . ' SET active=0 WHERE user_id IN ( ';
                foreach ($newUsers as $newUser) {
                    $_query.=$newUser. ' ,';
                }
                $_query = rtrim($_query, ',');
                $_query .=')';

Is a performant method of editing multiple table records at the same time? Exist faster ways?

thanks

Yes, this is performant. I don't are conscious of any faster way.

The UPDATE is okay. You may make your PHP a little more elegant while on an implode rather than looping using that array.

i.e.:

$_query = 'UPDATE ' . TABLE_A1 . ' SET active=0 WHERE user_id IN (' . implode(',', $newUsers) . ');'

You could include another contraint towards the query, that could speed up a tad more, but that is dependent how you receive your customers...

For those who have some customers which are already "active=", thou you can exclude them within the query with the addition of

.... where active<>0 and user_id in (...

This can prevent updates on fields that curently have the right value. I'd an identical query on the system oncce, also it was upgrading countless records which alreay contained the right information...