First entry

[Chris_Loke]

I have this big dataset were I want to select the first entry of the each customer by date in to the register so that I can put them in a new table/dataset were each customer is represented once.   

My dataset looks like this:

Data Have;

Customer_ID$   ent_date          Code$          
1                   1/1/2018             N06

1                   1/2/2018             A10

2                   3/5/2018             B20

2                   4/20/2018           B20

3                   5/27/2018           Y20

4                   9/1/2018             N06AA

4                   9/16/2018           A10B

4                   10/12/2018         B20.

Data Want;

Customer_ID$   ent_date          Code$          
1                   1/1/2018             N06

2                   3/5/2018             B20

3                   5/27/2018           Y20

4                   9/1/2018             N06AA

Thanks!

[novinosrin · Accepted solution]

data have;
input Customer_ID$   ent_date  :mmddyy10.        Code$    ;
format ent_date mmddyy10.;
cards; 
1                   1/1/2018             N06
1                   1/2/2018             A10
2                   3/5/2018             B20
2                   4/20/2018           B20
3                   5/27/2018           Y20
4                   9/1/2018             N06AA
4                   9/16/2018           A10B
4                   10/12/2018         B20
;

data want;
set have;
by customer_id;
if first.customer_id;
run;

/*or*/

data have;
input Customer_ID$   ent_date  :mmddyy10.        Code$    ;
format ent_date mmddyy10.;
cards; 
1                   1/1/2018             N06
1                   1/2/2018             A10
2                   3/5/2018             B20
2                   4/20/2018           B20
3                   5/27/2018           Y20
4                   9/1/2018             N06AA
4                   9/16/2018           A10B
4                   10/12/2018         B20
;


proc sql;
create table want as
select *
from have
group by customer_id
having min(ent_date)=ent_date
order by customer_id, ent_date;
quit;

[maguiremq]

In addition to @novinosrin you can use the nodupkey option on a proc sort step. You just have to sort it depending on the values you want. The data was already sorted here.

proc sort data=have nodupkey;
by customer_id;
run;

[Shmuel]

In case your data is already sorted by customer_id end_date then use @novinosrin solution

otherwise you need to sort data by both variables before sub-setting the data in order to have the first in date of each customer.

[Chris_Loke]

Thank you for replying to my question!

[Chris_Loke]

Thanks!