Agreed, but I like to add one further condition. When you have simplified it enough so that the people who need to use it can do so easily, without running to you with questions every time. ... View more

In the example you have provided,  you don't need the data set A at all.  You coudl simply forget about merging and just use: data C; set B; run; Please include an example where the data set A is needed. ... View more

So you posted the original question 4 hours ago.  Are you really saying that it would have taken longer than 4 hours to test it yourself? ... View more

Does the original question insist on using the IN operator?  It would be mildly simpler to use %INDEX: %macro ctrylist(ctry1); %let list1=AT AU CA CH; %put &list1; %if %index(&list1, &ctry1) %then %do; %put &ctry1; %end; %else %do; %put ERROR: &ctry1 is an invalid country code.; %put ERROR: Valid country codes include &list1..; %end; %mend ctrylist; %ctrylist(AU) %ctrylist(zz) In general, if you start with simpler tools, adding the complexity of macro language can produce a simpler result. ... View more

Just addressing the question you asked (no comment on the approach or the programming tools used), this would need to change: IF date <= put(31DEC20&yy.) THEN delete; Here's the correct way to refer to a particular date in SAS: IF date <= put("31DEC20&yy."d) THEN delete; But really you don't even need to go that far.  Refer to the date in your programming statements: if date <= "31DEC20&yy."d then delete; No functions needed.  ... View more

@PaigeMiller , thanks for the mention.  Unfortunately the book "Macro Language Magic" is now out of print, and I have been retired and without SAS for more than 5 years now. Off the top of my head, the most common "mysterious" need for %unquote is when macro language creates a list of quoted items for use in a WHERE clause within SQL code.  Many times the software figures out to unquote a list, but not when SQL is involved.   ... View more

Not the same thing but, it's my favorite "audience bet".   Playig backgammon, and rolling two dice, rolling "doubles" is advantageious (1:1, 2:2, ... 6:6). Chances of doubles on a single roll is 1 out of 6.  I claim that my opponent is exceedingly lucky and if he rolls the dice only 5 times, he will roll doubles at some point. The math is much easier than the question with three colors of balls. ... View more

A couple of good starting points ... As others have pointed out, we don't know what the log says, so we are only guessing ... This into: phrase looks incorrect: into :Basin1-, :BasinName- It should likely be: into :Basin1-, :BasinName1- And later when using the macro variables, are the basins actually numbers, or are they character strings?  For numbers, your code is correct: where Basin=&&Basin&i; But for character strings you would need to add doublequotes: where Basin="&&Basin&i";   ... View more

Here's a variation that gives you all the data you might ever want ... but lets you postpone the typing of all the variable names until you know the numbers you want.  There is no way to avoid naming the variables you want however.  Apologies for stealing bits of code here and there from earlier posts. proc summary data=have nway; class id; var _numeric_; output out=minimums min=; output out=maxiimums max=; run; This gives you two new data sets (I'll describe just one).  MINIMUMS contains one observation per ID, with the smallest value of each numeric variable.  You don't have to name any of them, because this program re-uses the same variable name.  In MINIMUMS, there is one observation per ID, and EVENT_DT holds the minimum value of EVENT_DT from the original data.  So the same variable name gets re-used without any typing or inventing names on your part.   You can always decide later which of the output pieces you want to use in your report.  The price you pay for this simplicity is on the back end when it is more complex to select the pieces that you want.  Here are the hoops you might have to jump through when using the data: data want; merge have minimums (keep=id event_dt rename=(event_dt=firstdt)) maximums (keep=id event_dt rename=(event_dt=lastdt)); by id; run; You start with simplicity, as well as great flexibility.  But you can't totally get around your responsibility to name the variables you want to use. ... View more

Whichever function you choose (dif or lag), make sure it executes on every observation. If you skip observations where first.med is 0, the next observation will have an incorrect calculation. ... View more

Can't be sure what your question is.  But one fault with your program is that you sort the data set output27a.  But your program doesn't create that data set, it only creates results.output27a.  Just a typo?  Or truly a different data set? ... View more

Definitely a problem.  While unbalanced single quotes can create problems, this is a call to the macro DON %don The simplest version of this macro might be: %if &A=0 or &B=0 %then %createtable; ... View more

Here are some ancient papers that discuss this and similar issues.   Here's an ancient paper that discusses your original post plus more: How MERGE Really Works https://www.lexjansen.com/nesug/nesug99/ad/ad155.pdf   And here's a slightly less ancient paper that discusses other bizarre results with MERGE: Danger:  MERGE Ahead!  Warning:  BY Variable with Multiple Lengths https://support.sas.com/resources/papers/proceedings/proceedings/sugi28/098-28.pdf     ... View more