What potential issues can arise from not using the DISTINCT keyword in a query when dealing with duplicate values?

When not using the DISTINCT keyword in a query, duplicate values may be returned in the result set, leading to inaccurate data analysis or unnecessary processing. To solve this issue, you can simply add the DISTINCT keyword before the column names in the SELECT statement to ensure that only unique values are returned. 

<?php
// Connect to database
$connection = new mysqli('localhost', 'username', 'password', 'database');

// Query with DISTINCT keyword to retrieve unique values
$query = "SELECT DISTINCT column_name FROM table_name";
$result = $connection->query($query);

// Process the result set
if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        // Process each unique value
    }
}

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

Keywords

PHP MySQL DISTINCT duplicate values query

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