Are there any potential pitfalls or drawbacks to using mysql_num_rows() instead of COUNT() in PHP?

Using mysql_num_rows() to count the number of rows in a result set can be less efficient than using COUNT() directly in the MySQL query. This is because mysql_num_rows() fetches all rows from the result set before counting them, which can be slower for large result sets. To improve performance, it's recommended to use COUNT() in the MySQL query itself.

// Connect to the database
$conn = mysqli_connect("localhost", "username", "password", "database");

// Query to count rows using COUNT()
$query = "SELECT COUNT(*) FROM table_name";
$result = mysqli_query($conn, $query);

// Fetch the count
$row = mysqli_fetch_array($result);
$count = $row[0];

// Output the count
echo "Number of rows: " . $count;

// Close the connection
mysqli_close($conn);