Query most recent TWO entries per widget

Question

I have two tables. One (Widgets) has a list of widgets (ID, widget_name, color, etc...) and data about them. The other one (Tests) has a list of tests run on the widgets (ID, d

Answer 1

(assuming all dates for the same widget are unique)

select T.*
from Widget W
join Test T on T.widget_id = W.id
where T.date >= (
    select max(T2.date)
    from Test T2
    where T2.widget_id = W.id
    and T2.date < (
        select max(T3.date)
        from Test T3
        where T3.widget_id = W.id
    )
) 
or T.date == (
    select max(T2.date)
    from Test T2
    where T2.widget_id = W.id
)

Answer 2

If you need the two most recent tests overall, then

Select * From Tests T
Where (Select Count(*) From tests
       Where testDate > T.TestDate) < 2

If you need the two most recent tests for each Widget, then

Select * From Tests T
Where (Select Count(*) From tests
       Where WidgetId = T.WidgetId 
           And testDate > T.TestDate) < 2