> 
> A lost update occurs when two different transactions are trying to
>  update the same column on the same row within a database at the same
>  time. Typically, one transaction updates a particular column in a
>  particular row, while another that began very shortly afterward did
>  not see this update before updating the same value itself. The result
>  of the first transaction is then "lost", as it is simply overwritten
>  by the second transaction. --<https://morpheusdata.com/blog/2015-02-21-lost-update-db>
> 
> 
> 

[![enter image description here](https://i.stack.imgur.com/xqoBg.png)](https://i.stack.imgur.com/xqoBg.png)