Mysql count performance on very big tables

Question

I have a table with more than 100 millions rows in Innodb.

I have to know if there is more than 5000 rows where the foreign key = 1. I don\'t need the exact number.<

Answer 1

If you are using PHP you could do mysql_num_rows on the result you got from SELECT primary FROM table WHERE fk = 1 => 0.6 seconds, I think that will be efficient.

But depends on what server-side language you are using