Why is it recommended not to use "SELECT *" in SQL queries and how can this be improved in PHP?

Using "SELECT *" in SQL queries is not recommended because it can lead to performance issues and potential security vulnerabilities. Instead, it is better to explicitly list the columns you want to retrieve in the query. This allows for better optimization of the query execution and reduces the risk of retrieving unnecessary data or exposing sensitive information. 

// Explicitly list the columns you want to retrieve instead of using SELECT *
$query = "SELECT column1, column2, column3 FROM table_name";
$result = mysqli_query($connection, $query);

// Example of iterating over the query results
if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_assoc($result)) {
        echo $row['column1'] . ' - ' . $row['column2'] . ' - ' . $row['column3'] . '<br>';
    }
}

Keywords

SQL queries SELECT * performance security PHP functions

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