I have 3 questions relating prayer of Qiyaam al-Layl & Tahajjud.
Islam Stack Exchange is a question and answer site for Muslims, experts in Islam, and those interested in learning more about Islam. It only takes a minute to sign up.Sign up to join this community
Qiyaam al-layl means spending (part of) the night in acts of worship and is more general than Tahajjud, while Tahajjud is part of it.
Obviously you must have the intention to perform the action for it to be counted as an act for worship.
This question is invalid as as they are related not mutually exclusive.