Find medain for each customer from multiple rows and remerge back with raw data

[Ronein]

Hello
I want to calculate for each customer median  of variable X and then to re-merge it with the original data set.

Thank you so much

Data tbl1;
input ID ddate x;
cards;
1 1901 15
1 1902 18
1 1903 22
1 1904 16
1 1905 35
1 1906 18
1 1907 21
2 1901 10
2 1902 15
2 1903 13
2 1904 15
2 1905 30
2 1906 30
2 1907 28
3 1901 40
3 1902 40
3 1903 40
3 1904 40
3 1905 40
3 1906 40
3 1907 40
;
run;

[PeterClemmensen · Accepted solution]

Do like this

proc sql;
    create table tbl2 as
    select *, median(x) as median_x
    from tbl1
    group by ID;
quit;