"Do you know why did he make that decision ?" vs. "Do you know why he made that decision ?"

Question

Is there any connotation difference between these two questions :

"Do you know why did he make that decision ?"

and :

"Do you know why he made that decision ?"

?

Answer 1

"Do you know why he made that decision?" is a correctly built question.

"Why he made that decision" is the object of the sentence (do you know (what?) why he made that decision?)

It's not right to try to build 2 questions within 1 sentence.

Making the object of the sentence, use the affirmative sentence word order:

Do you know why he did that?

Do you understand why I am doing this?

Do you realize how hard I have been trying?