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This is my first experience with mysqli. It seems to be looking for the name of a result set in between the parentheses in mysqli_num_rows(). Yet when I tried $stmt, $conn, and nothing, I got the same error. Frustrating! What goes where $WHAT is in the last line below?

Or maybe I'm trying the wrong tack. All I want to do is check that a result was returned. I don't really need the number of rows. Should I just do an else statement with an error message? Is that the best way to do it? And is there a good way to write a function to connect and accept the query and it's parameters? I wrote one for mysql but this is so different! I'm not looking forward to rewriting dozens of queries!

$conn = mysqli_connect($host, $user, $pwd, $db,$port=$port_nbr); 

if ($mysqli_connect_errno) {
    printf("Connect failed: %s\n",
    mysqli_connect_error());
    exit;
}
if($stmt=$conn->prepare("SELECT id, name, status, type FROM organization")) {
    $stmt->execute();
    $stmt->bind_result($org_id, $orgname, $orgstatus, $orgtype);    
    $num=mysqli_num_rows($WHAT);
}
dac
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  • [`mysqli_num_rows()`](https://www.php.net/manual/en/mysqli-result.num-rows.php) expects a result set identifier, but [`mysqli_prepare()`](https://www.php.net/manual/en/mysqli.prepare.php) returns a statement object. Compare [`mysqli_num_rows()`](https://www.php.net/manual/en/mysqli-result.num-rows.php) and [`mysqli_stmt_num_rows()`](https://www.php.net/manual/en/mysqli-stmt.num-rows.php). It might be confusing that both use a similar object oriented syntax: `$mysqli_result->num_rows` and `$mysqli_stmt->num_rows`. – showdev Aug 02 '19 at 07:17

3 Answers3

8

You're combining procedural and object oriented approaches, when you only want object oriented. Change

$num=mysqli_num_rows($WHAT);

to 

$num = $stmt->num_rows();
shmeeps
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  • No problem. Just remember, while you can intermix the two, it's usually better and less troublesome to pick one method and stick with it! – shmeeps Apr 23 '11 at 04:08
2

mysqli_num_rows takes the query result as a parameter http://us.php.net/manual/en/mysqli-result.num-rows.php

You could also use it in an OOP style as $result->num_rows;

Brian
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0

The reason for this error is that you may be passing the $stmt object to mysqli_num_rows().

Moreover, what I see is that you're mixing up two different approaches in php for using mysql databases - the Object-Oriented Approach and the Procedural Approach. You have to chose one of them and then proceed something like this -

Procedural Approach (Using mysqli extension)

$con = mysqli_connect("localhost", "user", "pass", "test") or die("Connection Error: " . mysqli_error($conn));
$query = "SELECT id, name, status, type FROM organization"; 
$result = mysqli_query($con, $query) or die(mysqli_error($con));
$count = mysqli_num_rows($result);

// $count now stores the number of rows returned from that query

Object-Oriented Approach (Using mysqli extension)

<?php
$host = "localhost";
$username = "user";
$password = "pass";
$dbname = "test";

// Create connection
$conn = new mysqli($host, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$sql = "SELECT id, name, status, type FROM organization";
$result = $conn->query($sql);
$count = $result->num_rows;
// $count now stores the number of rows returned
$conn->close();
?>

You can read more about it here - https://www.w3schools.com/php/php_mysql_select.asp

Harshit Budhraja
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