mysqli_statement::num_rows() returns the wrong value
Question
I was writing a database handler class in PHP using the mysqli class and prepared statements. I was attempting to print out the result. It didn't work right off the bat so I decided to do some debugging. I tried to use the num_rows()
method from the mysqli_statement
class, but it kept returning 0. I decided to write a small portion of test code to keep it simpler so I could see what was going wrong. I was then able to return the data I wanted, but the num_rows()
method still returns 0 even when it is actually selecting and retrieving some data. Here is the code:
$mysqli = new mysqli('localhost', 'username', 'password', 'database');
if(mysqli_connect_errno())
{
die('connection failed');
}
$statement = $mysqli->stmt_init();
$query = "SELECT name FROM table WHERE id = '2000'";
if($statement->prepare($query))
{
$statement->execute();
$statement->bind_result($name);
$statement->fetch();
$statement->store_result();
echo $statement->num_rows();
echo $name;
}
else
{
echo 'prepare statement failed';
exit();
}
So yeah, expected result is:
1name
And actual result is:
0name
Can anyone tell me why this is?
Solution
I wonder if num_rows() is reporting relative to the current resultset. Try capturing num_rows() prior to fetching the data. e.g.
if($statement->prepare($query))
{
$statement->execute();
$statement->store_result();
echo $statement->num_rows();
$statement->bind_result($name);
$statement->fetch();
echo $name;
}
Does that have any effect?
OTHER TIPS
num_rows is not a method, it's a property.
It doesn't look like you've declared $name.
Also, try removing bind_result() and fetch() so it reads something like this:
$statement->execute();
$statement->store_result();
printf("Number of rows: %d.\n", $statement->num_rows);