How can syntax errors in SQL queries be avoided when using PHP and MySQLi?

To avoid syntax errors in SQL queries when using PHP and MySQLi, it is important to properly format the SQL query string and use prepared statements to prevent SQL injection attacks. Prepared statements separate the SQL query from the data, reducing the risk of syntax errors. Additionally, using error handling techniques such as checking for errors after executing the query can help identify and resolve any syntax issues. 

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

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

// Prepare a SQL query with placeholders
$stmt = $mysqli->prepare("SELECT * FROM users WHERE username = ?");

// Bind parameters to the placeholders
$stmt->bind_param("s", $username);

// Set the parameter values
$username = "john_doe";

// Execute the query
$stmt->execute();

// Check for errors
if ($stmt->error) {
    die("Error: " . $stmt->error);
}

// Fetch the results
$result = $stmt->get_result();

// Process the results
while ($row = $result->fetch_assoc()) {
    echo $row['username'] . "<br>";
}

// Close the statement and connection
$stmt->close();
$mysqli->close();

Keywords

PHP MySQLi SQL queries syntax errors error handling

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