What is the purpose of using INNER JOIN in PHP when working with multiple tables?

When working with multiple tables in a database, the INNER JOIN clause in PHP is used to combine rows from two or more tables based on a related column between them. This allows you to retrieve data that is spread across multiple tables and display it in a single result set. 

<?php
// Connect to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);

// Select data from multiple tables using INNER JOIN
$sql = "SELECT users.username, orders.order_id, orders.total_price 
        FROM users
        INNER JOIN orders ON users.user_id = orders.user_id";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // Output data of each row
    while($row = $result->fetch_assoc()) {
        echo "Username: " . $row["username"]. " - Order ID: " . $row["order_id"]. " - Total Price: " . $row["total_price"]. "<br>";
    }
} else {
    echo "0 results";
}

$conn->close();
?>

Keywords

INNER JOIN PHP multiple tables database SQL

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