How can the use of DISTINCT in SQL queries affect the performance of a PHP application?

Using DISTINCT in SQL queries can affect the performance of a PHP application by increasing the query execution time and potentially causing slower page load times. To mitigate this issue, you can optimize your SQL queries by using appropriate indexes, refining your query logic, or limiting the use of DISTINCT to only when necessary. 

// Example of optimizing SQL query without using DISTINCT
$sql = "SELECT column1, column2 FROM table_name WHERE condition GROUP BY column1, column2";
$result = $conn->query($sql);

// Process the query result
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        // Process each row
    }
} else {
    echo "0 results";
}

Keywords

DISTINCT SQL queries performance PHP application optimization

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