I am using time use survey 2019 in India.I have extracted 5 datasets of different levels.In level5 extracted data ,I couldn't generate weights for some observations in that datasets.I don't know if I should drop those or replace missing weights with other ways .When I am merging all the datasets except level5 ,the commands look effective .But when I am trying to merge them with level5 ,the problem arises.It shows "your Id doesn't uniquely identify ..." .please help me .