SAS Vlookup in the same table

Question

my case is finding value in this same table (for Variable2 from Value). Can you help me? I need a SAS code for this case.

I tried to solve this way:

data example2;                                                 
 input Variable Value Variable2;                                                  
    datalines;                                                    
    V1 3 V2 
    V2 6 V1 
    V3 4 V5 
    V4 1 V1 
    V5 5 V2 
    ;

    proc sort data=example2;
        by Variable;
    run;
    data example19;
      set example2;
      merge example2 example2 (keep=Value Variable2 rename=(Value=new));                             
    run;  

Answer 1

below code should work for your scenario. I have checked for couple of edge case scenarios and it works as expected. Just check once again if it fails any edge case other this

 data have;
  input variable $ value variable2 $;
  datalines;
  V1 3 V2
  V2 6 V1
  V3 4 V5
  V4 1 V1
  V5 5 V2
 ;


   proc sql;
  create table want as 
     select  a.variable ,a.value, a.variable2 ,   b.value as value2            
  from have a
  left join
  have b
  on  a.variable2 =b.variable
  order by variable;

proc sql;
 select * from want;

/* once edge case scenario where you do not have variable for variable2 it 
  works as expected giving a null value*/

data have1;
 input variable $ value variable2 $;
datalines;
V1 3 V2
V2 6 V1
 V3 4 V5
V4 1 V1
V5 5 V2
V9 8 V7
 ;