One way to do to it:

if ($('#myselect option').length == 0) {
    $('#myselect').hide();
}

var $select = $('input:select option');
if(!$select.length )
    $select.attr('disabled', true);

Or:

$('select:not(:has(option))').attr('disabled', true);

Another way to do it is simply use the jQuery has function

if ($('#myselect').has('option').length == 0) 
{
    // Hide and disable select input here
}

For information on the jQuery has function see: https://api.jquery.com/has/