Not in a single select statement since you have missing values. Use different select statements
data test;
infile datalines dlm=',' dsd missover;
input House $ Portfolio $ City $;
datalines;
eson Str,1,London
Portabello,2,Peru
Munopolis,3,Lisbon
duncaster,4,New York
,5,Los Angeles
,6,
,7,
,8,
;
run;
proc sql ;
select quote(trim(House)) into:List_house separated by ''
from test
where House is not null;
select quote(trim(Portfolio)) into:List_portfolio separated by ''
from test
where Portfolio is not null;
select quote(trim(City)) into:List_city separated by ''
from test
where City is not null;
quit;
%put &List_house;
%put &List_portfolio;
%put &List_city;
Thanks,
Suryakiran