Filtering by Document ID in Sphinx

I wanted to exclude a certain document ID from within Sphinx:

sql_query = \
    SELECT u.id as u_id from users u
sql_attr_uint = u_id

and then in PHP:

$sphinxClient->addFilter('u_id', $userId, true);

As you are unable to filter directly on IDs, this approach yielded no results.

What you need to do is create a copy of the column and alias it for your attribute:

sql_query = \
    SELECT u.id, u.id as u_id from users u
sql_attr_uint = u_id

Now using the previous PHP to add the filter should return the results as expected.