topic Merging document with proc SQL or other procedure in SAS Programming

Merging document with proc SQL or other procedure

mlogan — Mon, 16 May 2016 19:30:27 GMT

Hi all,

I always merge tables with the following method which require me to sort both tables by BY field. Is there a better way where I don't have to sort the table before merging?

This is what I had been doing:

DATA Want;
MERGE have1(in=a) 2ave2(in=b);
BY common_variable;
IF a=1;
RUN;

Thanks,

Re: Merging document with proc SQL or other procedure

Astounding — Mon, 16 May 2016 19:51:11 GMT

The most common replacement would be a SQL left join. Here's a paper that talks about more variations than you might want to see:

http://www2.sas.com/proceedings/sugi30/249-30.pdf

There are other, more complex methods, including creating an index, hashing, creating a format. But SQL would definitely the place to begin.

If you are concerned about getting identical results to the MERGE, you have to consider whether any data sets might have more than one observation per value of COMMON_VARIABLE. If both data sets might have more than one, you have to ask yourself what the result should be ... not an easy topic.

Re: Merging document with proc SQL or other procedure

SASKiwi — Mon, 16 May 2016 19:56:51 GMT

You could do the same thing in SQL. Behind the scenes SQL still sorts your data but you avoid having to sort it yourself. SQL isn't necessarrily better, just different:

proc sql;
  create table want as 
  select *
  from have1 as a
  left join have2 as b
  on a.common_variable = b.common_variable;
  ;
quit;