It is a method to insure that the variables in the new data step match the variable definitions in the old dataset. The IF statement will treat 0 as false so it will never actually execute the SET statement, but the compiler will look at it and define all of the variables in that dataset. This will prevent the variable SITE from being defined as length $2. ... View more

Wow. That was some loaded comments . I started learning/using SAS since 2009, and I have been through lots of pains you just mentioned. I am not an expert, but fwiw this is how I learn: 1. Expose yourself to countless SAS problems as much as possible, meaning get actively engaged in SAS-L or here. Not necessarily posting answers, but at least trying to solve them by yourself. 2. Get down to the very basics, as deep as possible. Concepts such as PDV, data step implicit loop, SAS compiling, SAS execution, Macro compiling, Macro execution, etc, you NEED to know them inside-out, not just WHAT and HOW, most importantly, WHY. If you can think like SAS, then SAS will like your code. Read the text-book SAS papers written by Ian Whitlock,  Ron Cody, Paul Dorfman among many others. Touching down the specifics of your 'loop' comments,  sorry I can't agree with you. In the case of explicit loop, such as Do-Loop, you can use a index to identity the sequence, while in the case of data step implicit loop, _n_ is your guy. However, to echo with your sentiment, One thing about SAS, good or bad,  is that it has lots of default behaviors for the sake of better efficiency or memory management, keep in mind SAS originated decades ago where there was a completely different world.  Sometimes there is not that much you can do except getting used to it, meaning: memorizing it. My 2 cents, Haikuo ... View more

Yes, indeed that is my point.  Just simply create empty tables: proc sql;      create table A (id num,avar num);      create table B (id num,avar num);      create table C (id num,avar num); quit; Then in your macro, rather than creating a dataset, just do: data a;      set a some_other data; run; ... View more

I am pretty sure using the syntax select * from connection to xyz () will not be able to submit that type of code as its a query expecting a dataset back.  It may be that certain PL/SQL elements can be passed through by the use of execute() in a proc sql, per this post: Still begs the question why though? ... View more

Cynthia, Thank you for your advice, Cynthia! Yes, I have done some Proc report before by creating pdf, html output and they all work fine with styles and compute block. I will try this with TagSets.Excelxp and see how it  goes. Tao ... View more

Hi Gergely, Hi Thank you fro your reply!  Yes, as you described if there are 3 rows in the range, then yes, I want to keep all of them. The codes you mentioned below, I have think about this method by creating a new table with two extra columns as t1=time-29 and  t2=time-31. However, I didn't continue because I don't think you can join two tables without common variable. Your code just remind me that I can actually do cartesian join Thank you for the help again and I will try the code and see how it goes. Tao ... View more