In the following data step, table 1 and table 2 have the same data structure. Setting multiple tables in the data step will stack the tables. First, the where statement will make the program more efficient by applying the conditions to all the datasets in the Set statement. If statements create subsets and apply action(s) to specific subsets.
Data temp;
set table1 table2;
where var1 = ‘condition1’ and var2 = ‘condition2’ and var3 NE ‘condition3’;
if var4 = a and var5 = ‘3’ then do; output; end;
if var4 = b and var5 IN (‘1′,’2’) then do; output;end;
run;