item_count.patch

--- a/vendor/magento/module-quote/Model/ResourceModel/Quote.php
+++ b/vendor/magento/module-quote/Model/ResourceModel/Quote.php
@@ -220,13 +220,18 @@
         $connection = $this->getConnection();
         $subSelect = $connection->select();
 
+        // FIX force the new value for items_count to be > 0 and respect the column attribute UNSIGNED
+        $conditionCheck = $connection->quoteIdentifier('q.items_count') . " > 0";
+        $conditionTrue = $connection->quoteIdentifier('q.items_count') . ' - 1';
+        $ifSql = "IF (" . $conditionCheck . "," . $conditionTrue . ", 0)";
+
         $subSelect->from(
             false,
             [
                 'items_qty' => new \Zend_Db_Expr(
                     $connection->quoteIdentifier('q.items_qty') . ' - ' . $connection->quoteIdentifier('qi.qty')
                 ),
-                'items_count' => new \Zend_Db_Expr($connection->quoteIdentifier('q.items_count') . ' - 1')
+                'items_count' => new \Zend_Db_Expr($ifSql)
             ]
         )->join(
             ['qi' => $this->getTable('quote_item')],