What is the purpose of using the DISTINCT keyword in a MySQL query?

When querying a database, sometimes there may be duplicate rows returned that you want to eliminate. In such cases, you can use the DISTINCT keyword in a MySQL query to only return unique rows, removing any duplicates. This can be useful when you only want to see distinct values in a specific column or when you want to ensure that each row returned is unique. 

<?php
// Connect to database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);

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

// Query with DISTINCT keyword to select unique rows
$sql = "SELECT DISTINCT column_name FROM table_name";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // Output data of each row
    while($row = $result->fetch_assoc()) {
        echo "Column Value: " . $row["column_name"] . "<br>";
    }
} else {
    echo "0 results";
}

$conn->close();
?>

Keywords

PHP MySQL DISTINCT query purpose

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