I have a table called `foo` with columns like the following:

```
id 
usedId (id of the person who posted this foo)
title
postedDate

```

What I want to do, is add another column called `position`, which will record how many `foo`s a user has posted. E.g, his first posted `foo` will have the position of 1, 2nd will have 2, 100th will have 100, and so on. But this position is specific to the `userId` only.

Is there a way to add such a column to mysql, or I must calculate the position programatically?