Can this multi-step process be reduced to one proc sql statement? - sas

Question

I've been trying to make my code more efficient and this is the original code, but I think it can be written in one step.
data TABLE;set ORIGINAL_DATA;
Multi=percent*total_units;
keep Multi Type;
proc sort; by Type;
proc means noprint data=TABLE1; by Type; var Multi;output out=Table2(drop= _type_ _freq_)sum=Multi;run;
proc means noprint data=Table1; var Multi;output out=Table3(drop= _type_ _freq_) sum=total ;run;
proc sql;
create table TABLE4as
select a.Type, a.Multi label="Multi", b.total label="total"
from TABLE2 a, TABLE3 b
order by Type;
quit;
data TABLE5;set TABLE4;
pct=(MULTI/total)*100;
run;
I am able to split up part of it, but I can't figure out how to get the PCT part in my code. This is what I have.
proc sql;
create table TABLE1 as
select distinct type, sum(percent*total_units) as MULTI label "MULTI",
MULTI/(percent*total_units)) as PCT
from ORIGINAL_DATA
group by type;
quit;
I had to edit some of the code but I think the general idea should make sense.
The main problem is I cannot call upon the MULTI column because it is just being created but I want to create a percentage of the total for each type.

Answer 1

The "SAS" way to do something like this is to use a CLASS statement with PROC MEANS. That will calculate statistics on all the interaction levels in the data (identified by the TYPE variable). The row where TYPE=0 will be the "total" value, representing the value of that statistic for the entire data set.
In your case, we can take advantage of the fact that PROC MEANS will create the output data set sorted by TYPE and by the variables listed in the CLASS statement. That means we can just read the first observation and save it's value for calculating percentages.
It's probably easier to just show some code:
data TABLE;
set ORIGINAL_DATA;
Multi = percent * total_units;
keep Multi Type;
run;
proc means noprint data=TABLE;
class Type;
var multi;
output out=next sum=;
run;
data want;
retain total;
set next;
if _n_ = 1 then do;
/* The first obs will be the _TYPE_=0 record */
total = multi;
delete;
end;
pct = (multi / total) * 100;
drop total _freq_ _type_;
run;
Notice that you do not need to sort the data before using PROC MEANS. That's because we are using a CLASS statement rather than a BY statement. The data step is using the first observation in the data set created by MEANS (the TYPE=0 record) to retain the total sum of your variable. The delete statement keeps it out of the result.
CLASS statements with PROC MEANS are very useful. Take a few minutes to read up on how the TYPE variable is calculated, especially if you try using more than one class variable.

Answer 2

You can skip the initial data step by using the WEIGHT option in VAR statement of PROC MEANS (this will effectively do the multiplication for you). You can also use PROC TABULATE instead of PROC MEANS, as tabulate can calculate the percentage. I believe the following code will produce your required output in one go.
ods noresults;
proc tabulate data=have out=want (drop=_: rename=(total_units_sum=total total_units_pctsum_0=pct));
class type;
var total_units / weight=percent;
table type, total_units*(sum pctsum);
run;
ods results;

Answer 3

If you need one step, maybe this will work, but it's not actually efficient, since it processes data twice, once for detail by TYPE, once for total.
proc sql;
create table TABLE1 as
select
d.type
, sum(d.percent*d.total_units) as MULTI label "MULTI"
, calculated MULTI/s.total as PCT
from ORIGINAL_DATA d,
( select sum(percent*total_units) as total
from ORIGINAL_DATA) s
group by type
;
quit;
For more efficiency, but in more than one steps you could simply replace tables withe views in your original code:
data TABLE; => data TABLE / view=TABLE;
create table TABLE4 => create view TABLE4