$sql = "SELECT * FROM users"; $result = $conn->query($sql); $num_rows = $result->num_rows; echo "Number of rows: " . $num_rows;
$sql = "SELECT * FROM users WHERE username='johndoe'"; $result = $conn->query($sql); if ($result->num_rows > 0) { // do something } else { // do something else }In this example, "num_rows" is used to check if the query returned any rows. If the number of rows is greater than 0, then the code inside the "if" block will be executed. Otherwise, the code inside the "else" block will be executed. The "num_rows" function is part of the MySQLi (MySQL Improved) package library in PHP. This library provides an object-oriented interface to MySQL. It is a newer, more advanced library than the original MySQL library and includes features such as prepared statements and support for multiple statements. It is recommended to use MySQLi instead of the original MySQL library.