how to make two rows of data with same ID to have same value when one of them has blank

[ttqkroe]

ID	a	b	c	d	e	f
1	1	2	3	4	5	6
1	2		4		6

I want the result be:

ID	a	b	c	d	e	f
1	1	2	3	4	5	6
1	2	2	4	4	6	6

[novinosrin · Accepted solution]

data have;
input ID	a	b	c	d	e	f;
cards;
1	1	2	3	4	5	6
1	2	. 	4	. 	6	.
;

data want;
 update have(obs=0) have;
 by id;
 output;
run;

ID	a	b	c	d	e	f
1	1	2	3	4	5	6
1	2	2	4	4	6	6