problem with update

[PAVB]

Can't actually follow the logic of your code but I assume you are looking for something like:

SQL> set verify off
SQL> 
SQL> create table test999(empId number, empProject number);

Table created.

SQL> insert into test999 values(1, null);

1 row created.

SQL> insert into test999 values(2, null);

1 row created.

SQL> commit;

Commit complete.

SQL> select * from test999;

     EMPID EMPPROJECT
---------- ----------
         1
         2

SQL> accept empId prompt 'Enter empId:'
Enter empId:1
SQL> accept empProject prompt 'Enter empProject:'
Enter empProject:88888
SQL> 
SQL> update  test999
  2  set     empProject='&empProject'
  3  where   empId='&empId';

1 row updated.

SQL> commit;

Commit complete.

SQL> select * from test999;

     EMPID EMPPROJECT
---------- ----------
         1      88888
         2

SQL>