What is the purpose of using INNER JOIN in PHP when working with MySQL databases?

When working with MySQL databases in PHP, using INNER JOIN allows you to combine rows from two or more tables based on a related column between them. This is useful when you need to retrieve data from multiple tables that are connected by a common key, such as a foreign key relationship. INNER JOIN helps to eliminate rows that do not have a match in both tables, resulting in a more precise and targeted query result. 

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

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

$sql = "SELECT table1.column1, table2.column2
        FROM table1
        INNER JOIN table2 ON table1.id = table2.table1_id";

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

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

$conn->close();
?>

Keywords

INNER JOIN PHP MySQL databases purpose

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