[Grammar] ' sit AT the window' VS 'sit BY the window'

[northpath]

As far as I know, both prepositions AT and BY are OK in the sentence:
Don't sit AT/BY the window - it is very cold outside.
But what about the sentence:
After my promotion, I finally sit BY/AT the window.
Are they both OK in that sentence too? Or which one is more preferable?

 

[bhaisahab]

In the second one I would only use 'by'.

 

[northpath]

So, can I say that if someone is situated right at a window (he/she can tough the windowsill) then the preposition ‘at’ should be used. But if some is situated near or close to a window then the preposition ‘by’ should be used?

 

[jutfrank]

Use by in both sentences as you want to focus on proximity.

 

[northpath]

OK, to make it more clear, should I write:
I was sitting at the window and looking at a glorious sunset.

 

[jutfrank]

OK, to make it more clear, should I write:
I was sitting at the window and looking at a glorious sunset.

Yes, at is probably better here since the focus is on position and not proximity.