在SAS中如何检查数据集中的日期是否在另一个数据集中的日期范围内

Question

I have two data set Set1 and Set2.

Set1 data set has column Curr_Dt:-

Set1
Curr_Dt
23/04/1998
01/01/2017
01/12/2018
10/10/2010

Set2 data set has 3 columns St_Dt, End_Dt, Ind

  St_Dt              End_Dt               Ind
  01/11/2018        31/12/2018             N
  01/01/1998        31/05/1998             N
  30/11/2016        02/02/2017             N 

I want to update the Ind column of Set2 data set to Y if Curr_Dt from Set1 is falling in between St_Dt and End_Dt of Set2.

Answer 1

I don't see a key on here to merge by, so I am assuming that the first row goes with the first row and so down each data set.

You can do this with a simple Data Step.

data want;
merge set1 set2;

if st_dt <= curr_dt <= end_dt then
   ind = 'Y';
run;

This also assumes the dates are stored as dates and not strings.

Answer 2

Create sets

data Set1;
    length Curr_Dt $10;
    input Curr_Dt;
    cards;
23/04/1998
01/01/2017
01/12/2018
10/10/2010
;
run;

data Set2;
    length St_Dt $10 End_Dt $10 Ind $1;
    input  St_Dt$ End_Dt$ Ind$;
    cards;
01/11/2018 31/12/2018 N
01/01/1998 31/05/1998 N
30/11/2016 02/02/2017 N 
30/11/2005 02/02/2005 N 
run;

Set date formats

data Set1;
    set Set1;
    Curr = input(Curr_Dt, ddmmyy10.);
run;

data Set2;
    set Set2;
    St = input(St_Dt, ddmmyy10.);
    End = input(End_Dt, ddmmyy10.);
run;

Set Y flag if any Curr_Dt from Set1 falls between St_Dt and End_Dt

proc sql;
    create table Set2 as
    select distinct St_Dt, End_Dt,
    case when Set1.Curr>Set2.St and Set1.Curr<Set2.End
    then 'Y' else 'N' end as Ind
    from Set2
    left join Set1 on Set1.Curr>Set2.St and Set1.Curr<Set2.End;
run;

You get

01/01/1998  31/05/1998  Y
30/11/2016  02/02/2017  Y
01/11/2018  31/12/2018  Y
30/11/2005  02/02/2005  N