How can debugging techniques be applied to identify specific issues in PHP code, especially when working with databases?

Issue: When working with databases in PHP, a common issue is incorrect SQL queries leading to errors or unexpected results. To identify and fix this issue, debugging techniques such as printing out SQL queries before execution can be helpful in pinpointing the problem. Example PHP code snippet: 

// Connect to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

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

// Debugging SQL queries
$sql = "SELECT * FROM users WHERE id = 1";
echo $sql; // Print out the SQL query for debugging purposes

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

if ($result->num_rows > 0) {
    // Output data of each row
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 results";
}

$conn->close();

Keywords

PHP debugging techniques databases error handling troubleshooting

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