SAS: merge/ join datasets by dynamic columns in the look up table - sas

Question

I want to join sas dataset with the look up table but the column/key for joining is a value in the look up table
Dataset: table4
ID lev1 lev2 lev3 lev4 lev5
1 12548 14589 85652 45896 45889
2 12548 14589 85652 45896 45890
3 12548 14547 85685 45845 45825
4 66588 24647 55255 30895 15764
Look up table:
context table_name column operator value
extract table1 col1 equals xyd
asset table2 var1 equals 11111
asset table2 var2 equals 25858
prod table3 x1 equals 87999
unprod table4 lev2 equals 14589
unprod table4 lev2 equals 14589
unprod table4 lev3 equals 55255
Now I want to join table4 with lookup table but it is only possible with fields lev2 and lev3(it is dynamic so could be changed in the future, so don't want to hardcode in it).
I have tried below code but doesn't want to hard code as the fields are dynamic( someone might add lev4 as well in future).
proc sql ;
create table want as
select ID
from table4 as a
inner join lookup as b
on a.lev2 = input(value,12.) or a.lev3=input(value,12.)
where Context="unprod";
quit;
Thanks heaps in advance.

Answer 1

That does not look like a lookup table. It appears to be a set of rules. You could use it to generate code. Let's simplify the process by making the table contain actual code instead of three columns. But you could easily write the code to convert from your current format into code strings.
data rules ;
infile cards truncover ;
input context $ table_name $ rule $100. ;
cards;
extract table1 col1 = xyd
asset table2 var1 = 11111
asset table2 var2 = 25858
prod table3 x1 = 87999
unprod table4 lev2 = 14589
unprod table4 lev2 = 14589
unprod table4 lev3 = 55255
;
So now it looks like you want to take the rules that have a specific value of CONTEXT and use that to generate a new dataset from the dataset named in TABLE_NAME. Not sure what name you want to use for the generated table or what you want to do when more than one table is mentioned in the same "context".
%let context=unprod ;
filename code temp;
data _null_;
set rules ;
where context=symget('context');
by table_name ;
file code ;
if first.table_name then table_no+1;
if first.table_name then put
'data want' table_no ';'
/ ' set ' table_name ';'
/ ' where 1=0'
;
put ' or (' rule ')' ;
if last.table_name then put
';'
/ 'run;'
;
run;
%include code / source2 ;
Which results in code like this:
130 +data want1 ;
131 + set table4 ;
132 + where 1=0
133 + or (lev2 = 14589 )
134 + or (lev2 = 14589 )
135 + or (lev3 = 55255 )
136 +;
137 +run;
NOTE: There were 3 observations read from the data set WORK.TABLE4.
WHERE (lev2=14589) or (lev3=55255);
NOTE: The data set WORK.WANT1 has 3 observations and 6 variables.

Answer 2

Here is a sample code that would get what I understood you are trying to do. This code is based on the comment by #Reeza. If this is not what you are trying to do, please send a sample output file.
data table4;
input ID $ lev1 $ lev2 $ lev3 $ lev4 $ lev5 $;
datalines;
1 12548 14589 85652 45896 45889
2 12548 14589 85652 45896 45890
3 12548 14547 85685 45845 45825
4 66588 24647 55255 30895 15764
;
run;
data look_up;
input context $ table_name $ column $ operator $ value $;
datalines;
extract table1 col1 equals xyd
asset table2 var1 equals 11111
asset table2 var2 equals 25858
prod table3 x1 equals 87999
unprod table4 lev2 equals 14589
unprod table4 lev2 equals 14589
unprod table4 lev3 equals 55255
;
run;
PROC transpose DATA=work.table4 out=temp1 prefix=value;
by ID;
VAR lev1-lev5;
run;
proc sql;
create table want as
select a.*, b.ID
from look_up as a
inner join temp1 as b
on a.value=b.value1 and a.column=_Name_;
quit;