How can the JOIN command in MySQL be effectively used to retrieve and display data from multiple related tables in a PHP application?

When retrieving data from multiple related tables in a MySQL database in a PHP application, the JOIN command can be used to combine rows from two or more tables based on a related column between them. This allows for the retrieval of data from multiple tables in a single query, simplifying the process and improving performance. 

<?php
// Establish a connection to the MySQL database
$connection = new mysqli("localhost", "username", "password", "database");

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

// Query to retrieve data from multiple related tables using JOIN
$sql = "SELECT column1, column2, column3
        FROM table1
        JOIN table2 ON table1.id = table2.table1_id";

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

if ($result->num_rows > 0) {
    // Output data of each row
    while($row = $result->fetch_assoc()) {
        echo "Column1: " . $row["column1"]. " - Column2: " . $row["column2"]. " - Column3: " . $row["column3"]. "<br>";
    }
} else {
    echo "0 results";
}

$connection->close();
?>

Keywords

PHP MySQL JOIN command data retrieval related tables

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