If the order of the fruit in the output isn't critical this appears to work. If you need to keep order, then add a variable to All_fruit to use to sort on and the PROC sql code would use an ORDER BY clause with that variable after the On comparison within the same ; to close the query. data ALL_FRUIT; input Customer_No Fruit $ Amount  Sale_Type $; datalines; 100 Banana           5  Package 100 Apple           2  Package 100 Orange           3  Package 200 Banana           5  Only 300 Apple           2  Package 300 Orange           3  Package 400 Banana           5  Package 400 Apple           2  Package 400 Orange           3  Package 500 Banana           5  Package 500 Apple           2  Package 500 Orange           3  Package 600 Apple           2  Only 700 Orange           3  Only 800 Apple           2  Package 800 Banana           5  Package 900 Banana           5  Only 1000 Banana           5  Package 1000 Orange           3  Package ; run; Data BANANAS_ONLY; input Customer_No Fruit $ Amount  Sale_Type $; datalines; 100 Banana           5  Package 200 Banana           5  Only 400 Banana           5  Package 500 Banana           5  Package 800 Banana           5  Package 900 Banana           5  Only 1000 Banana           5  Package ; run; Proc sql; create table new_all_fruit as select a.*, case       when a.Sale_Type = 'Only' then ''       when missing(b.Customer_No) then ''       when a.fruit ne b.fruit then 'Yes'      end as Banana_package from All_fruit as a left join BANANAS_ONLY as b    on a.Customer_No=b.Customer_No; quit;     ... View more