Check a checkbox if value is present in a db table

I am populating checkboxes from data that I get from a database table. My question is different from other questions on SO because I have one checkbox defined and it loops when populated from the db. So I want to check the checkboxes that contains the values that are present in another table. With the code I have, only the checkbox with the values from the last row of the table is checked. What am I doing wrong?

    //this is the value I get from the other table.
    $indb = "$bid,$c,$sc,$p";

    $q5=mysqli_query($link,"SELECT * FROM brands_offer WHERE Brand_Id='$bid' AND Published='1' ");
    while($row5 = mysqli_fetch_array($q5)){
        $catid= $row5['Catg_Id'];
        $subcatid= $row5['Subcatg_Id'];
        $pid= $row5['Product_Id'];      

        //this is the value that populates the checkboxes
        $vals="$bid,$catid,$subcatid,$pid";
    ?>
    //my argument is here
    <input type="checkbox" name="checkbox[]" value="<?php echo "$vals";?>" <?php if ($vals == $indb){?> checked="checked" <?php } ?>>
    <?php
        echo $bname;
        echo " ->  ";
        echo $catid;
        echo ",  ";
        echo $subcatid;
        echo ",  ";
        echo $pid;
        echo "  ";
    }