How can one troubleshoot issues with queries not returning results in PHP?

If queries are not returning results in PHP, it could be due to errors in the query syntax, connection to the database, or the data being queried does not exist. To troubleshoot this issue, check the query syntax for errors, ensure the database connection is established correctly, and verify that the data being queried actually exists in the database. 

// Example code snippet for troubleshooting queries not returning results in PHP

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

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

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

// Example query that is not returning results
$sql = "SELECT * FROM table WHERE column = 'value'";

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

// Check if the query returned any results
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";
}

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

Keywords

MySQL SQL debugging error handling data retrieval

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