What potential issues can arise when comparing string values in PHP, especially when retrieving data from a database?

When comparing string values in PHP, especially when retrieving data from a database, potential issues can arise due to case sensitivity. To avoid this, you can convert both strings to lowercase or uppercase before comparing them. This ensures that the comparison is done in a case-insensitive manner.

// Retrieve data from the database
$databaseValue = "Hello";
$userInput = "hello";

// Convert both strings to lowercase before comparing
if(strtolower($databaseValue) === strtolower($userInput)) {
    echo "Strings are equal!";
} else {
    echo "Strings are not equal!";
}