mysql中如何更新两行是否相同

Question

this code is select item name and update value

and i want if item name and company name is same then update

like that

  $result = mysql_query("UPDATE stock SET  quantity=quantity - $quantity  WHERE itemname='$itemname',company='$company'")

but its not working it is showing this error

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'company=='xyz'' at line 1

original code and this is working

  $result = mysql_query("UPDATE stock SET  quantity=quantity - $quantity  WHERE itemname='$itemname'")

how can i do this please help me

thanks

Answer 1

使用AND运算符：

WHERE itemname='$itemname' AND company='$company'