PHP mysqli_num_rows(): Get The Number Of Rows In The Query Result

The mysqli_num_rows() function in PHP is used to return the number of rows in a result set. This function is very useful when you want to know how many rows are returned in a SELECT query, or how many rows are affected by a DELETE, INSERT, REPLACE, or UPDATE query.

Here's a simple tutorial on how to use the mysqli_num_rows() function.

Firstly, you'll need to establish a connection to your MySQL database using mysqli_connect().

// Database credentials
$db_host = 'localhost';
$db_user = 'username';
$db_pass = 'password';
$db_name = 'database_name';

// Create connection
$conn = mysqli_connect($db_host, $db_user, $db_pass, $db_name);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

Next, you can use a SELECT query to get data from your database:

// SQL query
$sql = "SELECT * FROM table_name";

// Execute query and get result
$result = mysqli_query($conn, $sql);

if ($result) {
    // Use mysqli_num_rows() to get the number of rows
    $num_rows = mysqli_num_rows($result);

    echo "Number of rows: " . $num_rows;
} else {
    echo "Error: " . mysqli_error($conn);
}

In this example, mysqli_query() executes the SQL query and returns a result set. Then, mysqli_num_rows() is used to get the number of rows in that result set.

Lastly, don't forget to close the connection when you're done:

// Close connection
mysqli_close($conn);

Important: The mysqli_num_rows() function will only return the correct number of rows on SELECT statements. For DELETE, INSERT, REPLACE, or UPDATE statements, use mysqli_affected_rows() instead.

Counting rows in MySQL result set with mysqli_num_rows():

The mysqli_num_rows() function is used to get the number of rows in a result set.

<?php
$mysqli = new mysqli('localhost', 'username', 'password', 'database');

// Check connection
if ($mysqli->connect_error) {
    die('Connection failed: ' . $mysqli->connect_error);
}

// Execute a SELECT query
$result = $mysqli->query('SELECT * FROM users');

// Get the number of rows
$rowCount = mysqli_num_rows($result);

echo "Number of Rows: $rowCount";

// Close the connection
$mysqli->close();

How to use mysqli_num_rows() in PHP:

Use mysqli_num_rows() on the result set obtained from a SELECT query.

<?php
$result = $mysqli->query('SELECT * FROM products');
$rowCount = mysqli_num_rows($result);

echo "Number of Rows: $rowCount";

Checking if a MySQL query returned any rows in PHP:

Use mysqli_num_rows() to check if any rows were returned.

<?php
$result = $mysqli->query('SELECT * FROM orders');
$rowCount = mysqli_num_rows($result);

if ($rowCount > 0) {
    echo "Rows found!";
} else {
    echo "No rows found!";
}

Examples of mysqli_num_rows() function in PHP:

Various examples of using mysqli_num_rows() in different scenarios.

<?php
$result1 = $mysqli->query('SELECT * FROM customers');
$rowCount1 = mysqli_num_rows($result1);

$result2 = $mysqli->query('SELECT * FROM products WHERE price > 50');
$rowCount2 = mysqli_num_rows($result2);

echo "Rows in Customers Table: $rowCount1, Rows with Price > 50: $rowCount2";

Handling conditional statements with mysqli_num_rows():

Use mysqli_num_rows() in conditional statements.

<?php
$result = $mysqli->query('SELECT * FROM messages WHERE status = "unread"');
$rowCount = mysqli_num_rows($result);

if ($rowCount > 0) {
    echo "You have unread messages!";
} else {
    echo "No unread messages.";
}

Retrieving the number of rows in a SELECT query in PHP:

Use mysqli_num_rows() to count rows in a SELECT query.

<?php
$result = $mysqli->query('SELECT * FROM books');
$rowCount = mysqli_num_rows($result);

echo "Number of Books: $rowCount";

Using mysqli_num_rows() for result set validation in PHP:

Validate the result set using mysqli_num_rows() before processing.

<?php
$result = $mysqli->query('SELECT * FROM employees WHERE department = "IT"');

if ($result && mysqli_num_rows($result) > 0) {
    // Process the result set
} else {
    echo "No employees found in the IT department.";
}

Common issues and troubleshooting with mysqli_num_rows():

Check for errors and handle issues with mysqli_num_rows().

<?php
$result = $mysqli->query('SELECT * FROM products');

if ($result === false) {
    die('Query failed: ' . $mysqli->error);
}

$rowCount = mysqli_num_rows($result);

echo "Number of Rows: $rowCount";

Alternative methods to get the number of rows in PHP MySQLi:

Consider using other approaches like COUNT(*) or fetching all rows and counting in PHP.

<?php
// Using COUNT(*)
$result = $mysqli->query('SELECT COUNT(*) FROM users');
$rowCount = $result->fetch_row()[0];

// Fetching all rows and counting in PHP
$result = $mysqli->query('SELECT * FROM orders');
$rowCount = $result->num_rows;

echo "Number of Rows: $rowCount";