Using macro variables/language in PROC SQL - sql

Question

I use PROC SQL for Oracle database queries (I'm not a db person though, so I can't be more specific than that), and we often apply formats from a library that is automatically loaded. I was wondering if there's a faster way to program these types of queries, for example let's say I have a variable called prim_disease_cd in a view, and I want to pull that out, apply the format (which has the same name) and also call it prim_disease_cd. Right now I would do
put(a.prim_disease_cd, prim_disease_cd.) as prim_disease_cd
Is there a way I can shorten this using macro language? I have been unsuccessful so far, but we do this often and it seems quite inefficient. Essentially I want a macro that takes in a view/dataset a and a variable X and applies "put (a.X, X.) as X"
Additionally, if there's anyway I can implement something like this for dates too that would be great, i.e. to replace
datepart(a.(var_name)) as (var_name) format mmddyy10.
Thanks for any help you can provide.

Answer 1

You could create simple macros to do those two things. Macros that emit just a portion of a statement like that are often referred to as macro functions or function style macros. Make sure not to emit any semi-colons. For example you might make these two macros.
%macro decode(alias);
%local varname ;
%let varname=%scan(&alias,-1,.);
put(&alias,&varname..) as &varname
%mend;
%macro datepart(alias);
%local varname ;
%let varname=%scan(&alias,-1,.);
datepart(&alias) as &varname format yymmdd10.
%mend;
Then your SQL query might look like:
create table want as
select a.patid
, %decode(a.prim_disease_cd)
, %datepart(a.onset_date)
from oralib.diagnosis a
;
You might find that the use of the these will make your SAS code much harder to maintain. It might be easier to find a way to automate the generation of the text in your editor instead. Or running a program that generates the text from the metadata and then just copy and paste it into your program.
PS Don't use MDY (or DMY) format for dates. It will just confuse your European (or American) friends.

Answer 2

If ever need to use the <concept>_cd code values in a future query against the Oracle data I would say create a new variable such as <concept>_value or simply <concept>.
If the coded data in the Oracle query is named consistently, such as only <concept>_cd, you can have a macro examine the pulled data and create a SAS view that applies the mapping from code to value via SAS format. Since you are pulling the coded values from Oracle, there is likely one or more lookup tables in Oracle that map the code to the value, and possibly your SAS formats are built from that data.
In your use case, transforming code to value is, in essence, performing left joins against the supposed lookup table or tables. I would presume you are performing the code mapping so that it is easier to perform subset selections.
If you are only reporting the data, you may only need to apply the format to the code variable itself. Here is a sample macro that post processes a query result and performs code to value mappings according to naming convention <concept>_cd
data code_lookups;
length id 8 fmt $31 desc $50 ;
input id & fmt & desc;
datalines;
1 country_cd US
2 country_cd Canada
10 color_cd Green
11 color_cd Blue
12 color_cd Red
20 footwear_cd Shoes
21 footwear_cd Socks
22 footwear_cd Laces
run;
proc format cntlin=code_lookups(rename=(fmt=fmtname id=start desc=label));
run;
data have(label="Some result from Oracle with unmapped codes");
input item_id country_cd color_cd footwear_cd;
datalines;
1 1 11 22
2 2 11 21
3 1 12 22
3 1 10 20
run;
%macro auto_codemap (data=, out=, out_struct=view, map_func=new_var);
%local dsid i l p q varname;
%let dsid = %sysfunc(open(&data));
%if &map_func ne format_only and &map_func ne new_var %then %do;
%put ERROR: &=map_func unknown.;
%end;
proc sql;
create &out_struct &out as
select
%do i = 1 %to %sysfunc(attrn(&dsid,nvar));
%if &i > 1 %then %str(,);
%let varname = %sysfunc(varname(&dsid,&i));
&varname
%let l = %length(&varname);
%if &l > 3 %then %do;
%let p = %eval(&l-3);
%let q = %eval(&l-2);
%if %substr(%upcase(&varname),&q) = _CD %then %do;
%if &map_func = format_only %then %do;
format=%str(&varname).
%end;
%else %if &map_func = new_var %then %do;
, put(&varname, %str(&varname).) as %substr(&varname,1,&p)
%end;
%end;
%end;
%end;
from &data
;
quit;
%let dsid = %sysfunc(close(&dsid));
%mend;
options mprint;
%auto_codemap (data=have, out=want)
proc print data=want;
run;
%auto_codemap (data=have, out=want2, map_func=format_only)
proc print data=want2;
run;