PHP & MYSQL: using group by for categories

Question

My database has the following setup

productid | productname | category id

and I want to output them like so:

category #1
it         


        

Answer 1

I'd recommend just a simple query to fetch all the rows, sorted by category id. Output the category only if its value changes from the previous row.

 query("SELECT * FROM `myTable` ORDER BY categoryID");

$current_cat = null;
while ($row = $stmt->fetch()) {
  if ($row["categoryID"] != $current_cat) {
    $current_cat = $row["categoryID"];
    echo "Category #{$current_cat}\n";
  }
  echo $row["productName"] . "\n";
}

?>