What best practices should be followed when handling SQL queries in PHP to prevent errors like "Argument #1 ($mysql) must be of type mysqli"?

When handling SQL queries in PHP, it is important to ensure that the connection object passed to the query functions is of the correct type, which is `mysqli`. To prevent errors like "Argument #1 ($mysql) must be of type mysqli", make sure to initialize the database connection using `mysqli_connect()` or `new mysqli()` and pass this connection object to the query functions. 

// Correct way to handle SQL queries in PHP using mysqli connection object

// Create a mysqli connection object
$mysqli = new mysqli("localhost", "username", "password", "database");

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

// Example SQL query
$query = "SELECT * FROM table_name";
$result = $mysqli->query($query);

// Handle the query result
if ($result) {
    // Process the result
} else {
    echo "Error executing query: " . $mysqli->error;
}

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

Keywords

SQL queries PHP mysqli error handling data validation

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