How to Use mysqli_num_rows in PHP to Get the Number of Rows in a Result Set

When using PHP for database operations, you may need to obtain the number of rows in a result set. PHP provides the convenient function mysqli_num_rows for this purpose.

Below is a sample code that demonstrates how to use mysqli_num_rows to retrieve the row count from a result set:

connect_errno) {
    echo "Failed to connect to database: " . $mysqli->connect_error;
    exit();
}

// Execute a query
$query = "SELECT * FROM users";
$result = $mysqli->query($query);

// Verify that the query executed successfully
if (!$result) {
    echo "Query failed: " . $mysqli->error;
    exit();
}

// Use mysqli_num_rows to get the number of rows in the result set
$num_rows = mysqli_num_rows($result);

// Output the result
echo "Number of rows in the result set: " . $num_rows;

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

In the example, we first connect to the database, execute a SELECT query, and store the result set in the $result variable. We then call mysqli_num_rows to obtain the row count, store it in $num_rows , and finally echo the count.

Note that mysqli_num_rows should only be used after a successful query; if the query fails, the result set contains no data and the function returns 0.

Summary

Using the PHP function mysqli_num_rows provides an easy way to determine the number of rows returned by a query, which is useful for checking whether data was retrieved and for counting query results.

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