There is not a default input Data Set (_last_ is _null)

[workoutpal]

When I run PROC CLUSTER, I get an error 

There is not a default input Data Set (_last_ is _null)

I am using SAS 9.4

I think my issue is loading tables.  I must be doing something very wrong with tables that look fine when I click on the contents under explorer.  Some of the code, I can get code to work if I create the data in the program using cards but some of the tables I am using are a few hundred and I eventually want to do a few thousand.  So, I need to load the data, and most of the examples I see do not show both the code and the output.

I put the raw data in an exel file, then I load the excel, and I see the correct column headings.

When I perform proc contents data=file, I see the variables.

But, if I try to use ID or VAR, I get errors.

[Tom · Accepted solution]

It will only try to use the default (&SYSLAST) dataset if you forget to TELL it what dataset to use in your code.

proc cluster data=use_this_dataset ...

[workoutpal]

Adding the data file to the command works.  How do I make an input data command the default data used in the program? 

Is there something like default data =  work.tablename?