组合两个表并在数组中显示它们的数据

Question

我有2个表:产品和购物车,我希望将这两个表组合在一起,并根据特定条件在数组中显示数据,如下所示:

应显示特定类别下的所有产品,如果特定用户在给定产品中购买了任何产品,则其详细信息也应显示在该产品的前面

我到目前为止所做的代码是

$catid = $_REQUEST['catid'];
$userid     = $_REQUEST['userid'];

$sql = "select * from productsize where catid = '".$catid."' GROUP BY productid";
$result = mysqli_query($con, $sql);
if (mysqli_num_rows($result) > 0) 
    {
        while($row = mysqli_fetch_assoc($result))
            { 
                $rows['catid'] =  $row['catid'];
                $rows['catname'] =  $row['catname'];
                $rows['productid'] =  $row['productid'];
                $rows['prodname'] =  $row['prodname'];
                $rows['prodimg'] =  $row['prodimg'];
                $row2[]=$rows;
            }   
    }

echo "<pre>";
print_r($row2);
echo "</pre>";

它给出了这样的数组

 Array
(
    [0] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 13
            [prodname] => P1
            [prodimg] => 
        )

    [1] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 14
            [prodname] => P1
            [prodimg] => 
        )

    [2] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 15
            [prodname] => P3
            [prodimg] => 
        )

)

但我想要的最后一个数组代替上面的数组是

Array
(
    [0] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 13
            [prodname] => P1
            [prodimg] => 
            [size] => Array
                (
                    [0] => small
                    [1] => medium
                    [2] => large
                    [3] => perpiece
                )
            [cost] => Array
                (
                    [0] => 10
                    [1] => 20
                    [2] => 30
                    [3] => 12
                )
            [purchasedsize] => Array
                (
                    [0] => small
                    [1] => 0
                    [2] => large
                    [3] => 0
                )
            [purchasedquantity] => Array
                (
                    [0] => 2
                    [1] => 0
                    [2] => 1
                    [3] => 0
                )
            [userid] => 1
        )

    [1] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 14
            [prodname] => P1
            [prodimg] => 
            [size] => Array
                (
                    [0] => small
                    [1] => medium
                    [2] => large
                    [3] => 0
                )
            [cost] => Array
                (
                    [0] => 15
                    [1] => 20
                    [2] => 25
                    [3] => 0
                )
            [purchasedsize] => Array
                (
                    [0] => 0
                    [1] => medium
                    [2] => 0
                    [3] => 0
                )
            [purchasedquantity] => Array
                (
                    [0] => 0
                    [1] => 1
                    [2] => 0
                    [3] => 0
                )
            [userid] => 1
        )

    [2] => Array
        (
            [catid] => 2
            [catname] => C1
            [productid] => 15
            [prodname] => P3
            [prodimg] => 
            [size] => Array
                (
                    [0] => 0
                    [1] => medium
                    [2] => 0
                    [3] => perpiece
                )
            [cost] => Array
                (
                    [0] => 0
                    [1] => 20
                    [2] => 0
                    [3] => 18
                )
            [purchasedsize] => Array
                (
                    [0] => 0
                    [1] => 0
                    [2] => 0
                    [3] => 0
                )
            [purchasedquantity] => Array
                (
                    [0] => 0
                    [1] => 0
                    [2] => 0
                    [3] => 0
                )
            [userid] => 0
        )

)

产品表的视图(正如您将看到产品表带有产品,每个产品下有最大4个尺寸(不会超过4个))

id  catid  catname  productid  prodsize   cost  prodname  prodimg
1    2       C1        13        small     10    P1
2    2       C1        13        medium    20    P1
3    2       C1        13        large     30    P1
4    2       C1        13        perpiece  12    P1
5    2       C1        14        small     15    P2
6    2       C1        14        medium    20    P2
7    2       C1        14        large     25    P2
8    2       C1        15        perpiece  18    P3
9    2       C1        15        medium    20    P3

推车桌看法

id   catid  catname  userid  productid  prodname  prodsize   quantity  prodcost
1       2      C1       1        13       P1       large        1         30      
2       2      C1       1        13       P1       small        2         10    
3       2      C1       1        14       P2       medium       1         20

任何人都可以帮助我获得所需的数组作为结果？