Why is it important to avoid using SELECT * in SQL queries and specify the columns instead in PHP?

Using SELECT * in SQL queries can cause performance issues and make the code harder to maintain. It's better to specify the columns you actually need in the query to improve performance and make the code more readable. By explicitly selecting the columns, you can also prevent unexpected behavior if the table structure changes in the future. 

// Avoid using SELECT * in SQL queries and specify the columns instead
$sql = "SELECT column1, column2, column3 FROM table_name";
$result = mysqli_query($conn, $sql);

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

Keywords

SQL queries SELECT * columns PHP performance

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