data test;
infile cards missover;
input x y;
cards;
19480 .
. 19659
19481 .
. 19701
19481 .
19481 .
. 19642
19481 .
. 19694
19484 .
19484 .
. 19625
1948 .
. 19656
19484 .
. 19745
19484 .
19485 .
. 19426
19485 .
19485 .
. 19626
19485 .
. 19626
19485 .
19485 .
. 19730
19485 .
. 19662
;
run;
data test1;
set test ;
z=coalesce(x, y);
run;