php num->rows not working - php

Question

I keep getting an error, even though I am 100% sure I followed the example that is found in the PHP manual.
The simplified version of the code can be found below.
note: connection to the database is ok.
EDIT: I keep getting an "Catchable fatal error: Object of class mysqli_stmt could not be converted to string" error.
EDIT: Now I keep getting "Mission Failed" even though I am sure that the row count should be 1.
Here's the coode used:
# $db = new mysqli('localhost', 'USER', 'PASSWORD', 'DATABSE');
$email = $db->prepare("select * from members where email = ?");
$email->bind_param('s', $email);
$email->execute;
$email->store_result;
$email->num_rows;
if ($email > 0) {
echo "<p>This e-mail is already in use, please try again with another e-mail.</p>";
exit;
} else {
echo "mission failed";
}
exit;
EDIT:
# $db = new mysqli('localhost', 'USER', 'PASSWORD', 'DB');
if ($db->connect_errno) {
echo "<p id=\"signup_confirmed\">Error: could not connect to database. Please try again later.</p>";
exit;
}
$checkRow = $db->prepare("select * from members where email = ?");
$checkRow->bind_param('s', $email);
$checkRow->execute;
$checkRow->store_result;
if ($checkRow->num_rows > 0) {
echo "<p id=\"signup_confirmed\">This e-mail is already in use, please try again with another e-mail.</p>";
exit;
} else {
echo "<p id=\"signup_confirmed\">Row checking has failed</p>";
}

Answer 1

change
$email->num_rows();
to
$email->num_rows;
in your code
New edit
$count = $email->num_rows;
if ($count > 0) {
echo "<p>This e-mail is already in use, please try again with another e-mail.</p>";
exit;
} else {
echo "mission failed";
}
More edit
change this to
$email = $db->prepare("select * from members where email = ?");
$email->bind_param('s', $email);
this
// you are over riding your $email value with the query thats the reason its not working
$query= $db->prepare("select * from members where email = ?");
$query->bind_param('s', $email);

Answer 2

# $db = new mysqli('localhost', 'USER', 'PASSWORD?', 'DATABSE');
$query_email = "select * from members where email = ?";
$email = $db->prepare($query_email);
$email->bind_param('s', $email);
$email->execute();
$email->store_result();
if ( $email->num_rows > 0) {
echo "<p id=\"signup_confirmed\">This e-mail is already in use, please try again with another e-mail.</p>";
exit;
}

Answer 3

$email is a result set, an object.
It will hold data returned from SQL operation.
You need to get the num_rows() in a variable.
Corrected code:
$cnt = $email->num_rows;
if ($cnt > 0) {
OR
if ($email->num_rows > 0) {

Answer 4

instead of
if ($email > 0) use if ($email->num_rows() > 0)