Conditionally delete the most recently inserted observation in SAS - sas

Question

I have two tables A and B that look like below.
Table A
rowno flag1 flag2 flag3
1 1 0 0
2 0 1 1
3 0 0 0
4 0 1 1
5 0 0 1
6 0 0 0
7 0 0 0
8 0 1 0
9 0 0 0
10 1 0 0
Table B
rowno flag1 flag2 flag3
Table A and B have the same column names but B is an empty table initially.
So what I want to accomplish is to insert the values from A to B row by row using macro, iteration by rowno. And each time I insert one row from A to B, I want to calculate the sum of each flag column.
If after insert each row, the sum(flag1) > 1 or sum(flag2) >1 or sum(flag3) >1, I need to delete that inserted row from table B. Then the iteration keeps running till the end of the observation in Table A. The final output in Table B is to have 5 observations from table A.
the code I have so far is below:
%macro iteration;
%do rowno=1 %to 10;
proc sql;
insert into table.B
select *
from table.A
where rowno = &rowno;
quit;
set table.B;
if
sum(flag1) > 1
or
sum(flag2) > 1
or
sum(flag3) > 1
then delete;
run;
%end;
%mend iteration;
%iteration
I received a lot of error messages.
Looking forward to your help and suggestions. Thanks.
The ideal output data would look like this
rowno flag1 flag2 flag3
1 1 0 0
2 0 1 1
3 0 0 0
6 0 0 0
7 0 0 0

Answer 1

Instead of a macro, use a running sum to calculate the running sum of each row. If you need to delete a row remember to reverse the increment to the running sum. Based on your data, I think Row 9 should also be kept.
data TableA;
input rowno flag1 flag2 flag3;
cards;
1 1 0 0
2 0 1 1
3 0 0 0
4 0 1 1
5 0 0 1
6 0 0 0
7 0 0 0
8 0 1 0
9 0 0 0
10 1 0 0
;
run;
data TableB;
set TableA;
retain sum_:;
*Increment running sum for flag;
sum_flag1+flag1;
sum_flag2+flag2;
sum_flag3+flag3;
*Check flag amounts;
if sum_flag1>1 or sum_flag2>1 or sum_flag3>1 then do;
*if flag is tripped then delete increment to flag and remove record;
sum_flag1 +-flag1;
sum_flag2 +-flag2;
sum_flag3 +-flag3;
delete;
end;
run;