What debugging techniques can be employed to troubleshoot issues with PHP code not producing the expected results when querying a database?

When troubleshooting issues with PHP code not producing the expected results when querying a database, you can employ the following debugging techniques: 1. Check for errors in your SQL query syntax. 2. Verify that the database connection is established correctly. 3. Use error handling to catch any exceptions or errors thrown during the query execution. 

// Example PHP code snippet for troubleshooting database query issues

// Establish a database connection
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

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

// Example SQL query
$sql = "SELECT * FROM table_name WHERE column_name = 'value'";

// Execute the query
$result = $conn->query($sql);

// Check for errors in query execution
if (!$result) {
    echo "Error: " . $conn->error;
}

// Process the query results
while($row = $result->fetch_assoc()) {
    // Output or process the data as needed
}

// Close the database connection
$conn->close();

Keywords

SQL injection var_dump error_reporting PDO Xdebug

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