What are the best practices for structuring a SQL query in PHP to avoid incorrect results when using GROUP BY?

When using GROUP BY in SQL queries in PHP, it is important to ensure that all non-aggregated columns in the SELECT statement are also included in the GROUP BY clause. Failure to do so can result in incorrect results being returned. To avoid this issue, always include all non-aggregated columns in the GROUP BY clause to ensure the query is structured correctly.

$query = "SELECT column1, column2, COUNT(*) 
          FROM table_name 
          GROUP BY column1, column2";
$result = mysqli_query($connection, $query);

while ($row = mysqli_fetch_assoc($result)) {
    // process the results here
}