How to substract sqty(solded_prod_var) from qty(purchase_variations) and update it in qty? [closed]

I want to substract sqty(solded_prod_var) from qty(purchase_variations) and update it in qty column from purchase_variations. I tried this.this is a table image of mysqli

<?php      session_start();      include("config.php");            if (isset($_POST['sale'])) {          $qtyupdt =SELECT tb.id, (tb.qty - tbl.sqty) n      FROM purchase_variations tb      LEFT JOIN solded_prod_var tbl ON (tbl.vid = tb.id);                foreach ($qtyupdt as $row){              $upd='UPDATE purchase_variations SET qty = ' . (int)$row['n'] . ' WHERE id = ' . (int)$row['id'] . ' LIMIT 1';      }      ?>  

https://stackoverflow.com/questions/66916254/how-to-substract-sqtysolded-prod-var-from-qtypurchase-variations-and-update April 02, 2021 at 04:02PM