What strategies can be used to prevent duplicate entries from being retrieved in PHP database queries?

To prevent duplicate entries from being retrieved in PHP database queries, you can use the DISTINCT keyword in your SQL query to only retrieve unique records based on the specified column(s). This ensures that only distinct rows are returned, eliminating any duplicates. 

// Connect to the 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 to retrieve unique records
$sql = "SELECT DISTINCT column_name FROM table_name";

$result = $conn->query($sql);

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

$conn->close();

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PHP database queries prevent duplicate entries strategies

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