Union All will include duplicates. Union will remove duplicates:
proc sql; create table table1 as select obs2,obs4 from table2 union select obs2,obs4 from table3 union select obs2,obs4 from table4;
2025 SAS Hackathon: There is still time!
Good news: We've extended SAS Hackathon registration until Sept. 12, so you still have time to be part of our biggest event yet – our five-year anniversary!