I have a basic question about SAS macro. Inside sas macro, when you write a let statement or a put statement or an if statement, you always prefix it with %.
But when you write a 'proc' inside a macro, why don't we need to write %proc? Or for example %data?
% denotes macro syntax - macro functions, macro statements, or macro commands. Basically, things that would be covered by the SAS Macro Language Reference.
When you have a proc in a macro, what you're asking the macro to do is to type that proc onto the stack as if you'd typed it. You don't need a % because the proc is the text you're asking be typed, not a command to the macro language interpreter itself.
SAS Macro language and SAS Base are two essentially separate languages - the latter is the core of SAS, the former is a helper that can make it easier to do certain repetitive things. They're only loosely integrated.
The %let or %put are macro statements: they are not the same thing as the put you can use in the data step. They share the name and basic idea of functionality, but nothing else any more than printf in c and printf in r share in common.