PHP PDO check if row exists or found

Counting or checking if your PDO MySQL query found a row relies on one key object called rowCount. rowCount returns the number of rows affected by the last executed query.

With this knowledge when you do a SELECT WHERE query the amount of rows that qualify the statement can be returned with rowCount.

Here is it in action:

$select = $db->prepare('SELECT username FROM users WHERE id = ?');
if ($select->rowCount() > 0) {
    //Row has been found
    //Do ......
} else {
    //No row found

A condition is in place for if rows affected is greater than 0, meaning we have found at least 1 row for our query. Otherwise no rows were found as $select->rowCount() is 0.