When I'm running the following query with + sign it is adding the values and showing correct result but when I replace + sign with - sign it is still showing the correct result but showing - sign before the result. Why is it displaying - sign in the result?
please help me to fix this issue thanks
ON DUPLICATE KEY UPDATE quantity='$quantity'-quantity ")
it is showing result like this
--------------
quantity row
--------------
-5
--------------
this is not working perfect
$result = mysql_query("INSERT INTO stock SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',category='$category',signature='$signature'
ON DUPLICATE KEY UPDATE quantity='$quantity'-quantity ")
this is working
$result = mysql_query("INSERT INTO stock SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',category='$category',signature='$signature'
ON DUPLICATE KEY UPDATE quantity='$quantity'+quantity ")
i m insert to query togetter this is my complete code but 1st one is working fine but 2nd one have problm
// save the data to the database
mysql_query("INSERT INTO recivereturn SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',category='$category',signature='$signature'");
$result = mysql_query("INSERT INTO stock SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',category='$category',signature='$signature'
ON DUPLICATE KEY UPDATE quantity=$quantity-quantity ")
You are almost certainly doing the subtraction backwards. You probably want to subtract a variable from the current value of the column, not vice versa:
ON DUPLICATE KEY UPDATE quantity = quantity - '$quantity'
Try like
"ON DUPLICATE KEY UPDATE quantity=".$quantity."-quantity ")
Like
$result = mysql_query("INSERT INTO stock
SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',
category='$category',signature='$signature'
ON DUPLICATE KEY UPDATE quantity= ".$quantity."+quantity ")
Please try once $quantity without quotes.
$result = mysql_query("INSERT INTO stock SET date='$date',company='$company',itemname='$itemname',quantity='$quantity',category='$category',signature='$signature'
ON DUPLICATE KEY UPDATE quantity=$quantity-quantity ");