What are common pitfalls when using mysql_query in PHP for retrieving data?

Common pitfalls when using mysql_query in PHP for retrieving data include not properly sanitizing user input, not checking for errors in the query execution, and not using prepared statements for security. To solve these issues, always sanitize user input to prevent SQL injection attacks, check for errors in the query execution, and use prepared statements to securely retrieve data from the database. 

// Example of using prepared statements with mysqli for retrieving data securely

// Establish a connection to the database
$mysqli = new mysqli("localhost", "username", "password", "database");

// Check for connection errors
if ($mysqli->connect_error) {
    die("Connection failed: " . $mysqli->connect_error);
}

// Prepare a statement with placeholders
$stmt = $mysqli->prepare("SELECT column1, column2 FROM table WHERE id = ?");

// Bind parameters to the placeholders
$stmt->bind_param("i", $id);

// Execute the statement
$stmt->execute();

// Bind the result variables
$stmt->bind_result($result1, $result2);

// Fetch the results
while ($stmt->fetch()) {
    echo "Result 1: " . $result1 . ", Result 2: " . $result2 . "<br>";
}

// Close the statement and connection
$stmt->close();
$mysqli->close();

Keywords

mysql_query PHP data retrieval SQL injection error handling

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