Question: How to explain the result of this direction limit?

I want to find limit of the function sqrt(x^2 - 3 x + 2) from the left of the point x = 2. I tried
limit(sqrt(x^2-3*x+2), x = 2, left)

I got the result 0.  I know that, the limit is not exits. How to explain the result of Maple?

Another example, 
limit(sqrt(x^2-3*x+2), x = 2, real)

I got the output 0.

With Mathematica, I see at here

Please Wait...