PHP/Laravel - Updating SQL integer column in row adds 1 to the value

Question

I have this weird problem, where I'm trying to update an entry into my SQL database and it keeps adding 1 when I increase the value of the column and save it.

For example, I += 1 to the existing value of an entry of 2, the result is 3, but when saved it is logged as 4 in the database... The column structure is int(20) unsigned.

PHP:

$quantity = 1;
$item = \App\item::find($item_id);
$item->items_sold += $quantity;
$item->save();

if I dd($item->items_sold) the result is correct, and the value is changed by the specified amount. However when I check the database, the value is increased by the specified amount and then increased again by 1...

Any help would be very much appreciated! Thankyou :)

Answer 1

查询生成器还提供了增加或减少给定列的值简便的方法见

\App\item::find($item_id)->increment('items_sold',1);