What are the risks of using SELECT * in SQL queries in PHP?

Using SELECT * in SQL queries can lead to performance issues and security risks. It can retrieve unnecessary columns, increasing the amount of data transferred between the database and the application. Additionally, it can make the code more prone to SQL injection attacks. To mitigate these risks, it's best to explicitly specify the columns you want to retrieve in your SELECT queries. 

// Specify the columns you want to retrieve instead of using SELECT *
$sql = "SELECT column1, column2, column3 FROM table_name";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // output data
    while($row = $result->fetch_assoc()) {
        echo "Column1: " . $row["column1"]. " - Column2: " . $row["column2"]. " - Column3: " . $row["column3"]. "<br>";
    }
} else {
    echo "0 results";
}

Keywords

SQL injection data leakage performance degradation security vulnerability database schema changes.

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