Hi all,   I have a dataset with following variables: Child Mother Country_Mother Country_Child 1 . . DE 2 1 DE GB 3 2 GB US 4 3 US ES 5 1 DE DK 6 5 DK FR 7 . . IT 8 . . NL 9 8 NL LU Each child has either no mother, one mother or several mothers in a chain upwards. If the child does not have a mother it is the "highest" mother in a chain. Then I need to assign in a new variable "New_Country" the country of this "highest" mother to all her children in a chain downwards without knowing the depth of the chain. For the highest mother itself (country_mother and mother is empty) new_Country should be filled in with country_child. The result table should look like this:   Child Mother Country_Mother Country_Child New_Country 1 . . DE DE 2 1 DE GB DE 3 2 GB US DE 4 3 US ES DE 5 1 DE DK DE 6 5 DK FR DE 7 . . IT IT 8 . . NL NL 9 8 NL LU NL   This table is only an excerpt to illustrate the data structure. The data set is actually longer and has many such chains. I've already tried using loops and index but it did not work. I read a lot about hashes and recursive queries but I'm not sure how to use them in this case, since I'm rather new in sas macros.   I'm very grateful for every help! Thanks, Jaus ... View more