Concatenate multiple result rows of one column into one, group by another column [duplicate]

I’m having a table like this

Movie   Actor   
  A       1
  A       2
  A       3
  B       4

I want to get the name of a movie and all actors in that movie, and I want the result to be in a format like this:

Movie   ActorList
 A       1, 2, 3

How can I do it?