Consider the following queries:

$1.$ SELECT $*$ FROM customer

WHERE support$\_$rep$\_$id IN

$($SELECT employee$\_$id FROM employee

WHERE first$\_$name $=$ 'Steve'$)$;

$2.$ SELECT customer.$*$ FROM customer

INNER JOIN employee

ON customer.support$\_$rep$\_$id $=$ employee.employee$\_$id

WHERE employee.first$\_$name $=$ 'Steve';

Which of these would be the most efficient?