@cosmid wrote: I am still unclear about question 1. The code used in the book is also a SET statement, why didn't that retain the value of the variables? I don't have the book, but variables read by a SET statement are automatically retained until their values are overwritten by the next execution of the SET statement (or any other statement changing those values).   Here is an example (log) using a PUT statement to show variable values in each iteration of a DATA step, before assignment statements and a SET statement are executed: 118 data _null_; 119 put _all_; 120 retvar='Ret'; 121 newvar=123; 122 set sashelp.class(obs=3); 123 retain retvar; 124 run; retvar= newvar=. Name= Sex= Age=. Height=. Weight=. _ERROR_=0 _N_=1 retvar=Ret newvar=. Name=Alfred Sex=M Age=14 Height=69 Weight=112.5 _ERROR_=0 _N_=2 retvar=Ret newvar=. Name=Alice Sex=F Age=13 Height=56.5 Weight=84 _ERROR_=0 _N_=3 retvar=Ret newvar=. Name=Barbara Sex=F Age=13 Height=65.3 Weight=98 _ERROR_=0 _N_=4 As you can see, in the second, third and fourth iteration of the DATA step (_N_=2, 3, 4) the variables from SASHELP.CLASS still contain the values read by the SET statement in the previous iteration of the DATA step. Similarly, starting with the second iteration, the value of the explicitly retained variable RETVAR is available before the assignment statement refreshing it. Variable NEWVAR, however, is not retained, hence reset to missing when the DATA step iterates and these newly created missing values are written to the log for _N_=2, 3, 4. Initially (_N_=1), the values of all variables (except the automatic variables _ERROR_ and _N_) were missing. ... View more

proc sql; create table chkfmt as select * from dictionary.formats; quit; proc print data=chkfmt heading=v width=min; run; ... View more

Good question!   One of the strange things about both CALL SYMPUTX() and CALL SYMPUT() is which symbol table it will use to create a new symbol (what most people normally call macro variables).   The strange thing is that SAS does not always create a symbol table for every running macro.  Macros that do not have any local macro variables do not get a symbol table defined.  In which case the new macro variable will be created in the next higher symbol table.  Which could be the local symbol table of the calling macro.   By adding a parameter to the macro definition they insured that the macro will have at least one local symbol so that there will be a local symbol table created when it runs.   Try this example. %macro nosymtable; * This macro will have no symbol table; data _null_; call symputx('nosymboltable','xxx'); run; %mend nosymtable; %macro makemvar(mvar,value); data _null_; call symputx("&mvar","&value"); run; %nosymtable; %put _user_; %mend makemvar; %makemvar(test2,yyy); What symbol table has the value xxx in the macro variable nosymboltable? MAKEMVAR MVAR test2 MAKEMVAR NOSYMBOLTABLE xxx MAKEMVAR TEST2 yyy MAKEMVAR VALUE yyy GLOBAL SQLEXITCODE 0 GLOBAL SQLOBS 1 GLOBAL SQLOOPS 136 GLOBAL SQLRC 0 GLOBAL SQLXOBS 0 GLOBAL SQLXOPENERRS 0 GLOBAL SYS_SQL_IP_ALL -1 GLOBAL SYS_SQL_IP_STMT ... View more

You will have to read the data to see if the values are there. If the datasets all have the same variables then you can read them all in one data step.   You can use the INDSNAME= option of the SET statement to know which dataset the current observation comes from.   So use a data step like this to read all of the data and keep the names of the datasets that have observations that match your criteria. data want; length dsname indsname $41 ; set dataset1-dataset50 indsname=indsname ; where x='c'; dsname=indsname; if dsname ne lag(dsname) then output; keep dsname; run; The only trouble you might have is getting the list of names into the SET statement if the names are not as simple as that.  In that case you might want to get the list into a macro variable.     For example if you want all of the datasets in the libref MYLIB that have a variable named X then the code might look like this instead: proc sql noprint; select distinct catx('.',libname,memname) into :memlist separated by ' ' from dictionary.columns where libname='MYLIB' and upcase(name)='X' ; quit; data want; length dsname indsname $41 ; set &memlist indsname=indsname ; where x='c'; dsname=indsname; if dsname ne lag(dsname) then output; keep dsname; run;  If the datasets might have conflicts for some other variable types (Variables other than X,  for example say Y is character in DATASET1 and numeric in DATASET2) then you will want to add a KEEP= dataset option to each dataset. ... View more