how to calculate the second day retention rate?

[booooosevic]

I have tables DIM_USER (user_key, user_id, register_date) DIM_DATE (date_key, date) FACT_USER_ACTIVITY (user_key, activity_id, date_key) Now I want to calculate the second day retention rate, literally it means the quantity of users registered on previous day who login in the app today / quantity of users registered on previous day I'm struggling on this issue for hours, could anyone give me some tips? Thanks in advance!

[booooosevic]

Sorry I post this thread on the incorrect board, moderator please delete this.