What potential issue could arise if the query in the PHP code does not return any matching records?

If the query in the PHP code does not return any matching records, the potential issue that could arise is that the code may throw an error or behave unexpectedly if it tries to access data that does not exist. To solve this issue, you can check if there are any rows returned by the query before trying to access the data. This can be done by checking the number of rows returned by the query result.

// Execute the query
$result = mysqli_query($connection, "SELECT * FROM table WHERE condition");

// Check if there are any rows returned
if(mysqli_num_rows($result) > 0) {
    // Fetch and process the data
    while($row = mysqli_fetch_assoc($result)) {
        // Process the data here
    }
} else {
    // Handle the case when no matching records are found
    echo "No matching records found.";
}