How to add new column in to a dataset in SAS using proc SQL?

Question

I am trying to add a new column to a dataset based on the binary condition of another column. However, I keep getting an error. My code below:

proc sql;
alter table data
    add Status (case WHEN missing(DeactReason) THEN 'Active' ELSE 'Inactive)'
   END;
quit;

However, I get the following error:

143  proc sql;
144  alter table data
145      add Status (case WHEN missing(DeactReason) THEN 'Active' ELSE 'Inactive)'
                    -
                    79
ERROR 79-322: Expecting a CHECK.

146     END;
           -
           79
ERROR 79-322: Expecting a ).

147  quit;

Thanks: EDIT: Corrected the code:

proc sql;
alter table table
    add Status (case WHEN missing(DeactReason) THEN 'Active' ELSE 'Inactive')
   END;
quit;

Get the following error now:

148  proc sql;
149  alter table table
150      add Status (case WHEN missing(DeactReason) THEN 'Active' ELSE 'Inactive')
                    -                                                            -
                    79                                                           22
                                                                                 76
ERROR 79-322: Expecting a CHECK.

ERROR 22-322: Syntax error, expecting one of the following: !, !!, &, *, **, +, -, /, <, <=,
              <>, =, >, >=, ?, AND, BETWEEN, CONTAINS, END, EQ, EQT, GE, GET, GT, GTT, IN, IS,
              LE, LET, LIKE, LT, LTT, NE, NET, NOT, NOTIN, OR, ^, ^=, |, ||, ~, ~=.

ERROR 76-322: Syntax error, statement will be ignored.

151     END;
152  quit;

Answer 1

The ALTER TABLE statement is used to add new columns, delete existing columns or modifying the format of columns. Afaik you cannot use CASE expressions within an alter table statement. You can do it within an UPDATE statement though.

proc sql;
    alter table data add status char label= "Status" format=$8.;
    update data set status=case when missing(DeactReason) then 'Active' else 'Inactive' end;
quit;

Answer 2

You cannot use the SQL ALTER statement to insert data.

But modifying an existing dataset is not a normal analysis step. Plus is is dangerous as if something goes wrong you might destroy your original dataset.

Just create a new dataset that has the additional information you want.

With SQL using PROC SQL.

proc sql;
  create table new as 
  select *
       , case WHEN missing(DeactReason) THEN 'Active' 
              ELSE 'Inactive' 
         END as STATUS
  from old
  ;
quit;

Or with normal SAS code.

data new; 
   set old;
   if missing(DeactReason) THEN STATUS='Active  ';
                           ELSE STATUS='Inactive';

run;