Hi Folks!,   Thanks for the case study like this. Expecting more cases to practice as a SAS developer .   Happy to share ! keep learning ! Keep inspiring !   Here's my solution for the given case study : data Tsunami; format DATE_TIME datetime19. Regioncode id best12.; set data.earthquakes_dirty; id=scan(id_regioncode,1,'-'); Regioncode=scan(id_regioncode,2,'-'); FLAG_TSUNAMI=upcase(FLAG_TSUNAMI); EQ_PRIMARY=coalesce(EQ_MAG_MW,EQ_MAG_MS,EQ_MAG_MB,EQ_MAG_ML,EQ_MAG_MFA,EQ_MAG_UNK); DATE_TIME=dhms(mdy(month,day,year),hour,minute,seconds); drop id_regioncode month day year hour minute seconds EQ_MAG_MW EQ_MAG_MS EQ_MAG_MB EQ_MAG_ML EQ_MAG_MFA EQ_MAG_UNK; run; proc sort data=Tsunami out=Tsunami1 dupout=dup_rec nodupkey; by id; run; proc sort data=Tsunami ; by id; run; data valid_tsunami invalid_tsunami; set Tsunami; if Regioncode in (1, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90,100, 110, 120, 130, 140, 150, 160, 170) and FLAG_TSUNAMI in (" ", "TSU") and not missing(DATE_TIME) and (0 <= EQ_PRIMARY <= 9.9) and (0 <= FOCAL_DEPTH <= 700) then output valid_tsunami; else output invalid_tsunami; run;   data invalid_final1; set invalid_tsunami dup_rec; run;   proc sql; select id into:dupid from dup_rec; quit; %put &=dupid; proc sql; create table invalid_final as select *, case when REGIONCODE not in (1, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90,100, 110, 120, 130, 140, 150, 160, 170) then 'Region Code' when EQ_PRIMARY < 0 or EQ_PRIMARY > 9.9 then 'EQ Primary' when FOCAL_DEPTH < 0 or FOCAL_DEPTH > 700 then 'Focal Depth' when EQ_PRIMARY=. and FOCAL_DEPTH=. then 'EQ Primary, Focal Depth' when DATE_TIME=. then 'DATE Time' when id=&dupid then 'Duplicate ID' end as INVALID_DESCRIPTION FORMAT=$50. from invalid_final1; quit; ... View more