We have a table that each row represents a visit hit (page view or event) abd we have corresponding visitor ID for each hit. I categorized each hit as ‘last 1 month’, ‘last 3 months’, ‘last 12 months’ etc. based on when each hit has happened compared to now (if 20 days ago, then it is L1M and also L3M and L12M but if it is 70 days ago then it is L3M and L12M but not L1M).
Now I want to show how many unique visitors in each category of L1M, L3M, L12M.
usually one user is under multiple category, if she visited in L1M then that means she has visited in L3M by default. They are not mutually exclusive. I need to ensure she is counted in both L1M and L3M etc.