Is there any default table to I use it as an alias?

I have this query:

$db
->prepare("INSERT INTO
             events (post_id, table_code, other_id, user_id, author_id, date_time )
             select ?, 15, ?, ?, ?, UNIX_TIMESTAMP()
              UNION ALL
             select ?, 15, ?, ?, ?, UNIX_TIMESTAMP()
               from (select 1) as a
              where 1=?
")->execute(array($answer_id, $answer_id, $author_ques_id, $author_ques_id,
                  $answer_id, $answer_id, $author_ques_id, $author_ans_id,
                  ($yourCondition?1:0) ));

Please focus on this line:

from (select 1) as a

My query works as well and all fine.

I just remember I read somewhere there is a default-table-name (something like double) which I can use it instead of (select 1) as a in this case. Anybody knows what's that?