如果get_result或fetch_array为空则不起作用

Question

I'm trying to make a message if there are no results to show from mysqli result:

$result = $stmt->get_result();

// I tried many things like this before the while

if (empty($stmt->get_result())) {
    // message here
}

// or

if (!$stmt->get_result()) {
    // message here
}

while ($row = $result->fetch_array()) {
    // do something
}

//Also after the while

if (empty($result->fetch_array())) {
    // message here
}

// or

if (!$result->fetch_array()) {
    // message here
}

But nothing works, I get the while printing data and the message also displaying... or not displaying nothing.

What is the correct way?

Thanks!

Answer 1

mysqli_stmt::get_result() will only return false on error, so looking for a negative is not a way to check for an empty result set. You can use the while loop in your example code to increment a counter and check its value after the fact. Or you can use the returned mysqli_result object and check its mysqli_result::$num_rows property.

You should continue checking for false as a return value though, in case there are errors on the database side of things. These can be displayed with mysqli::$error.