What alternative approach could be used to count the number of different planets in the database?

The issue with counting the number of different planets in the database is that the traditional approach of using a SQL query with COUNT() may not work if there are duplicate entries for the same planet. An alternative approach could be to retrieve all unique planet names from the database and then count the number of distinct names. 

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

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

// Query to retrieve unique planet names
$query = "SELECT DISTINCT planet_name FROM planets";
$result = $connection->query($query);

// Count the number of unique planet names
$num_planets = $result->num_rows;

// Display the count
echo "Number of different planets in the database: " . $num_planets;

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

Keywords

SQL COUNT DISTINCT GROUP BY JOIN PHP PDO

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