Insert and update using proc sql simultaneously in SAS - sas

Question

I am importing a file using proc import
proc import datafile="/opt/Export_d.csv" replace
out=work.export_data; run;
THEN I SELECTED 2 VARIABLES FROM EXPORTED TABLE HAVING SOME CONDITION
proc SQL;
create table work.login2
as select ' SURVEY_ID'n, TIME format=datetime20.,' USERNAME'n
from work.export_data
having TIME=max(TIME) and ' USERNAME'="sasdemo";
quit;
then i created a macro for survey_id because i have to update a value with the Survey_id reference in different table shown in below code:
proc SQL;
select max(' SURVEY_ID'n) into: sid from work.login2;
quit;
now if the ID is blank then i don't have to insert anything but if we have survey_id we have update few columns in a table using below code which is not happening.
proc SQL;
case when ' SURVEY_ID'n is not null then update table_name set SAS_TRACKING_CODE="&Trackingcode."
where SURVEY_ID=&sid.
else end;
quit;

Answer 1

The syntax in your proc sql is not valid. At all. case whencan only be used within statemements like select, where, order by.
The following will do your update if SURVEY_ID is not blank:
proc sql;
update table_name
set SAS_TRACKING_CODE="&Trackingcode"
where SURVEY_ID=&sid. and SURVEY_ID is not null
;
quit;
If what you want is to execute the update only when a condition is true, you should use a macro.
EDIT: that macro would look like this:
%macro update;
%if %symexist(sid) and not &sid = %then %do;
proc sql;
update table_name
set SAS_TRACKING_CODE="&Trackingcode"
where SURVEY_ID=&sid.
;
quit;
%end;
%mend;