Here's the query:

```
SELECT ID, Name, EventTime, State
FROM mytable as mm Where EventTime IN
(Select MAX(EventTime) from mytable mt where mt.id=mm.id)

```

Here is the fiddle:
<http://sqlfiddle.com/#!3/9630c0/5>
It comes from this S.O. question:
[Select distinct rows whilst grouping by max value](https://stackoverflow.com/questions/17814961/select-distinct-rows-whilst-grouping-by-max-value)

I would like to hear in plain english how it works. I'm missing some fundamental understanding of part of it.

I don't really understand what the aliases are doing in the mt.id=mm.id part. It selects rows where the id is equal to the id?