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how to update data in existing variables by using proc sql?

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Super Contributor
Posts: 297

how to update data in existing variables by using proc sql?

Hello:

 

I would like to use PROC SQL according to the following data steps.  I am thinking of using "update' statement and "Case...end".  However, I don't know how to work in the multiple variables. 

 

data dataout.recat1;

      set dataout.test;

      if age in (1,2,3,4,5) then age=1;

      if marital in (2, 4) then marital=2;

      if income in (1,2,3) then income=1;

run;

 

 

Super Contributor
Posts: 251

Re: how to update data in existing variables by using proc sql?

[ Edited ]

This is another difficult problem to solve accurately without having the source data available to test it. However this code wll work. Whether it's what you want is another thing:

proc sql;
create table dataout.recat1 as
select ifn(age in(1, 2, 3, 4, 5), 1, .) as age,
ifn(marital in(2, 4), 2, .) as marital,
ifn(income in(1, 2, 3), 1, .) as income
from dataout.test;
quit;

The first ifn function tests age to see if it's 1 - 5; if it is, age is reset to 1, but if not it's set to missing. The same pattern is in the next two lines. I use ifn or ifc if there are only going to be two possibilities; if there are more I use case/when/else.

 

If you want other variables in the output dataset, you need to specify them.

 

Note that you would only use update if you were replacing the dataset; in your datastep code you specify a different dataset.

Super Contributor
Posts: 297

Re: how to update data in existing variables by using proc sql?

I don't like set extra missing "." for 1-5 cause there are missing "." in original data.  It will cause the confusion.

Super Contributor
Posts: 251

Re: how to update data in existing variables by using proc sql?

That's why I pointed out the lack of data, and specification. Can you attach your source data and how you want the output to look? It's really hard otherwise.
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