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

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;