PHP If variable = a and not = b

php 7.3.18

mysql 5.7.30

Here is the relevant code, which fails immediately so I would appreciate it being corrected.

The first 'if' is ok, but the issue is with the 2nd + 3rd.

$targetcatid2, $targetcatid3, $targetweight2, $targetweight3 have been properly declared.

The object is that if a product is in Category2 and not in Category3 then the weight will become Weight2 and vice-a-versa.

$row2=mysqli_fetch_array($select2);

if($row2['category_id']== $targetcatid){
    $row['product_weight']= $targetweight;
}

if($row2['category_id']== $targetcatid2 && !== $targetcatid3){
    $row['product_weight']= $targetweight2;
}

if($row2['category_id']== $targetcatid3 && !== $targetcatid2){
    $row['product_weight']= $targetweight3;
}