query for parent

[Aexor]

I have a table like this:

Parent  Child

A            B

B            C

C            D

I             J

J           K

K          L

i want to write a query which which output values which are parent only having no child.

Output  A and I 

[sbxkoenk · Accepted solution]

I think this is what you want:

data have;
 input Parent $ Child $;
 cards;
A            B
B            C
C            D
I            J
J            K
K            L
;
run;

PROC SQL noprint;
 create table want as
 select Parent
 from have
 where Parent NOT IN (select Child from have)
;
QUIT;

dm 'FSV';
/* end of program */

Koen

[singhsahab]

@Aexor can be solve by using Hash Object 

data want;
if _n_ eq 1 then do;
declare hash h(dataset:'have');
h.defineKEY('Child');
h.definedata('parent');
h.definedone();
end;
do until ( eof2 ) ;
 set have end = eof2 ;
 if h.find(key:parent) ne 0 then 
 OUTPUT;
 end ;
 stop ; 
run;

 Regards,

 SS

[PeterClemmensen]

I suspect you want to know more than just A and I here?