Why is it recommended to avoid using the * wildcard in the SQL query when selecting columns from a table?

Using the * wildcard in an SQL query to select all columns from a table can lead to performance issues and potential security vulnerabilities. It is recommended to explicitly list the columns you want to select to improve query performance and prevent exposing sensitive data. By specifying the columns, you can also make your code more readable and maintainable. 

<?php
// Specify the columns you want to select
$sql = "SELECT column1, column2, column3 FROM table_name";
$result = mysqli_query($connection, $sql);

// Fetch and display the results
while ($row = mysqli_fetch_assoc($result)) {
    echo $row['column1'] . " - " . $row['column2'] . " - " . $row['column3'] . "<br>";
}
?>

Keywords

SQL query wildcard columns security performance

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