How can the use of SELECT * in SQL queries impact the performance and security of PHP applications?

Using SELECT * in SQL queries can impact the performance of PHP applications because it retrieves all columns from a table, even if not all columns are needed. This can result in unnecessary data being transferred between the database and the application, slowing down the query execution. Additionally, using SELECT * can pose security risks as it may expose sensitive information if new columns are added to the table in the future. To improve performance and security, it is recommended to explicitly specify the columns to retrieve in the SELECT statement rather than using SELECT *. This way, only the necessary data is fetched from the database, reducing the amount of data transferred and improving query performance.

<?php
// Specify the columns to retrieve in the SELECT statement
$sql = "SELECT column1, column2, column3 FROM table_name WHERE condition";

// Execute the query
$result = mysqli_query($connection, $sql);

// Process the results
while ($row = mysqli_fetch_assoc($result)) {
    // Process each row
}
?>