Used to work/have worked

The first was wrong, so I have fixed it.

1) I worked in that company for 3 years-- You no longer work there.

2) I have worked in that company for 3 years-- You still work there.
3) I used to work in that company three years ago.-- You stopped working there in 2007.

Thanks Mister Micawber,

For sentence 2) I have worked in that company for 3 years

What if I say I have been working in that company for 3 years, does it make any difference? Thanks.

Best regards,

Bernard

It makes it quite clear that you are still working there.

Thanks a lot.

Would saying this also be possible:
I worked in that company three years ago.

AnonymousWould saying this also be possible:I worked in that company three years ago.

Yes, but it does not say how long you worked there; it could have been only one week and then you were fired.

I was just comparing it with: I used to work in that company three years ago.

Does that sentence say how long I worked there? Doesn't seem like it.

What is the difference between them? And how can that I used to work in that company 3 years ago and for how long?

Also, does this show when and how long I worked there:
I worked in that company 3 years ago for 1 month.

Yes

How different between

I used to work for Japanese company for 2 years.

I have worked for Japanese company for 2 years.

I have been working for Japanese company for 2 years.

Thank you

Nick