SAS loop through datasets - sas

Question

I have multiple tables in a library call snap1:
cust1, cust2, cust3, etc
I want to generate a loop that gets the records' count of the same column in each of these tables and then insert the results into a different table.
My desired output is:
Table Count
cust1 5,000
cust2 5,555
cust3 6,000
I'm trying this but its not working:
%macro sqlloop(data, byvar);
proc sql noprint;
select &byvar.into:_values SEPARATED by '_'
from %data.;
quit;
data_&values.;
set &data;
select (%byvar);
%do i=1 %to %sysfunc(count(_&_values.,_));
%let var = %sysfunc(scan(_&_values.,&i.));
output &var.;
%end;
end;
run;
%mend;
%sqlloop(data=libsnap, byvar=membername);

Answer 1

First off, if you just want the number of observations, you can get that trivially from dictionary.tables or sashelp.vtable without any loops.
proc sql;
select memname, nlobs
from dictionary.tables
where libname='SNAP1';
quit;
This is fine to retrieve number of rows if you haven't done anything that would cause the number of logical observations to differ - usually a delete in proc sql.
Second, if you're interested in the number of valid responses, there are easier non-loopy ways too.
For example, given whatever query that you can write determining your table names, we can just put them all in a set statement and count in a simple data step.
%let varname=mycol; *the column you are counting;
%let libname=snap1;
proc sql;
select cats("&libname..",memname)
into :tables separated by ' '
from dictionary.tables
where libname=upcase("&libname.");
quit;
data counts;
set &tables. indsname=ds_name end=eof; *9.3 or later;
retain count dataset_name;
if _n_=1 then count=0;
if ds_name ne lag(ds_name) and _n_ ne 1 then do;
output;
count=0;
end;
dataset_name=ds_name;
count = count + ifn(&varname.,1,1,0); *true, false, missing; *false is 0 only;
if eof then output;
keep count dataset_name;
run;
Macros are rarely needed for this sort of thing, and macro loops like you're writing even less so.
If you did want to write a macro, the easier way to do it is:
Write code to do it once, for one dataset
Wrap that in a macro that takes a parameter (dataset name)
Create macro calls for that macro as needed
That way you don't have to deal with %scan and troubleshooting macro code that's hard to debug. You write something that works once, then just call it several times.
proc sql;
select cats('%mymacro(name=',"&libname..",memname,')')
into :macrocalls separated by ' '
from dictionary.tables
where libname=upcase("&libname.");
quit;
&macrocalls.;
Assuming you have a macro, %mymacro, which does whatever counting you want for one dataset.

Answer 2

* Updated *
In the future, please post the log so we can see what is specifically not working. I can see some issues in your code, particularly where your macro variables are being declared, and a select statement that is not doing anything. Here is an alternative process to achieve your goal:
Step 1: Read all of the customer datasets in the snap1 library into a macro variable:
proc sql noprint;
select memname
into :total_cust separated by ' '
from sashelp.vmember
where upcase(memname) LIKE 'CUST%'
AND upcase(libname) = 'SNAP1';
quit;
Step 2: Count the total number of obs in each data set, output to permanent table:
%macro count_obs;
%do i = 1 %to %sysfunc(countw(&total_cust) );
%let dsname = %scan(&total_cust, &i);
%let dsid=%sysfunc(open(&dsname) );
%let nobs=%sysfunc(attrn(&dsid,nobs) );
%let rc=%sysfunc(close(&dsid) );
data _total_obs;
length Member_Name $15.;
Member_Name = "&dsname";
Total_Obs = &nobs;
format Total_Obs comma8.;
run;
proc append base=Total_Obs
data=_total_obs;
run;
%end;
proc datasets lib=work nolist;
delete _total_obs;
quit;
%mend;
%count_obs;
You will need to delete the permanent table Total_Obs if it already exists, but you can add code to handle that if you wish.
If you want to get the total number of non-missing observations for a particular column, do the same code as above, but delete the 3 %let statements below %let dsname = and replace the data step with:
data _total_obs;
length Member_Name $7.;
set snap1.&dsname end=eof;
retain Member_Name "&dsname";
if(NOT missing(var) ) then Total_Obs+1;
if(eof);
format Total_Obs comma8.;
run;
(Update: Fixed %do loop in step 2)