Yes, a special variable named _type_ is created by several SAS procedures. ALSO, a variable named _type_ can be created in a data step:   For example:   data test;      input sales_id $                            sales_jn                            sales_fe                            sales_mr; datalines; W6790 50 400 350 W7693 25 100 125 W1387 99 300 250 ; run; data tot;      set test;            _type_ = sales_jn + sales_fe + sales_mr; run; data sel;      set tot(where=(_type_=250)); run;   OUTPUT: test sales_id sales_jn sales_fe sales_mr W6790 50 400 350 W7693 25 100 125 W1387 99 300 250   OUTPUT:  tot sales_id sales_jn sales_fe sales_mr _type_ W6790 50 400 350 800 W7693 25 100 125 250 W1387 99 300 250 649   OUTPUT: sel sales_id sales_jn sales_fe sales_mr _type_ W7693 25 100 125 250 ... View more