Summer SQL Teaser #4 Nulls and Counts

First create this table

CREATE TABLE Teaser (ID int)
INSERT Teaser VALUES(1)
INSERT Teaser VALUES(2)
INSERT Teaser VALUES(1)
INSERT Teaser VALUES(2)
INSERT Teaser VALUES(NULL)


Without running this try to figure out what the result will be

SELECT COUNT(*),
COUNT(ID),
COUNT(DISTINCT ID)
FROM Teaser


For some more NULL fun you can read NULL Trouble In SQL Server Land