mysql: get max id from two tables

[pedroz]

mysql query to know the max id in two tables

working:

                                 

$m1 = $db->sql_fetchrow($db->sql_query("SELECT MAX(id) FROM users")); 
$m2 = $db->sql_fetchrow($db->sql_query("SELECT MAX(id) FROM users_temp"));

$max = max($m1[0], $m2[0]);

echo $max

However...
I would like to know if there is a short query to get the $max value

[bpat1434]

SELECT MAX(id) FROM users JOIN users_temp USING(id)

That might work....