How do i populate the value to the remaining group of data that is currently empty?

[StickyRoll]

Hello, I have the following sample input data:

data sorteddata;
	POL_ID='AAA';
	POL_CLS='BLUE';
	POL_YEAR='2024';
	MAD_AGE = 26;
	output;

	POL_ID='AAA';
	POL_CLS='BLUE';
	POL_YEAR='2024';
	MAD_AGE = 21;
	output;

	POL_ID='AAA';
	POL_CLS='BLUE';
	POL_YEAR='2024';
	MAD_AGE = 56;
	output;

	POL_ID='BBB';
	POL_CLS='GREY';
	POL_YEAR='2025';
	MAD_AGE = 18;
	output;
run;

proc sort data=sorteddata;
by POL_ID POL_CLS POL_YEAR MAD_AGE; 
run;

I have the following code that will allow me to mark the first unique set of values with Flag ='Y'.

data mad_age;
	set sorteddata;
	by POL_ID POL_CLS POL_YEAR MAD_AGE;
	if first.POL_ID and first.POL_CLS and first.POL_YEAR and MAD_AGE then flag='Y';
run;

Once this is done, the column FLAG will have value 'Y' for every first record of POL_ID POL_CLS and POL_YEAR and MAD_AGE.

Now next step, how can i create a new field called "YOUNGEST_PLAYER" and for every first record of POL_ID POL_CLS POL_YEAR and MAD_AGE, for example, the age is 25 (so the value of FLAG = 'Y'), how do i populate 25 for the same group of other records belonging to the same POL_ID POL_CLS POL_YEAR combination?

For example:

POL_ID POL_CLS and POL_YEAR and MAD_AGE FLAG

1             A                         2024                    25                 Y

1             A                         2025                    70

1             A                         2025                    71

into

POL_ID POL_CLS and POL_YEAR and MAD_AGE FLAG YOUNGEST_PLAYER

1             A                         2024                    25                 Y          25

1             A                         2025                    70                              25

1             A                         2025                    71                               25

[PeterClemmensen · Accepted solution]

Since your data is already sorted the wayt you want it, you can do this

data want;
   set mad_age;
   by POL_ID POL_CLS POL_YEAR MAD_AGE;
   if first.POL_ID then youngest_player = mad_age;
   retain youngest_player;
run;

Result:

POL_ID  POL_CLS  POL_YEAR  MAD_AGE  flag  youngest_player
AAA     BLUE     2024      21       Y     21
AAA     BLUE     2024      26             21
AAA     BLUE     2024      56             21
BBB     GREY     2025      18       Y     18