Concatenate columns in ALTER statement in PROC SQL

[Saurabh_Rana]

How can I concatenate multiple columns in PROC SQL statement using ALTER? And I don't want to use SELECT statement since in that case, I will have to mention all the columns and the table on which I am working has more than 100 columns whereas in the ALTER statement you just need to mention the column you are adding.

[Kurt_Bremser]

The ALTER TABLE statement can be used to just add a column, but it will initialize it with missing values. You need to also use an UPDATE that sets the values as needed.

I would rather use a DATA step to do this (add a column and use concatenation of values to populate it).

[Saurabh_Rana]

But with the data step, I will only get the concatenated column in output table but I want the concatenated column along with the other 100 columns. What is the best way to achieve this output?

[Kurt_Bremser · Accepted solution]

You will get ALL variables, unless you drop them:

data have;
input x $ y $;
datalines;
a b
;

data want;
set have;
z = cats(x,y);
run;

proc print data=want noobs;
run;

Result:

  x    y    z

  a    b    ab