Oracle conditional update query

Question

I have one requirement as shown below :

Suppose we have EMP table with 5 rows having deptno = 20 --Here i will get deptno i.e.20 from input paramter

EMPNO   ENAME   JOB       MGR   HIREDATE    SAL     COMM    DEPTNO 
--------------------------------------------------------------------------------
7566    JONES   MANAGER   7839  04/02/1981  2975    -   20 
7788    SCOTT   ANALYST   7566  12/09/1982  3000    -   20 
7902    FORD    ANALYST   7566  12/03/1981  3000    -   20 
7369    SMITH   CLERK     7902  12/17/1980  800     -   20 
7876    ADAMS   CLERK     7788  01/12/1983  1100    -   20 

Now I want to write one UPDATE query in procedure which will update EMP Table set JOB = 'MANAGER' where empno in (7788,7902); -- Here empno i.e. 7788 and 7902 i will get from input parameter

My update query Should update JOB = 'MANAGER' for 2 rows having deptno = 20 and for rest of 3 rows i want to update will Null values.

So that final output will be as shown below :

EMPNO   ENAME   JOB       MGR   HIREDATE    SAL     COMM    DEPTNO 
--------------------------------------------------------------------------------
7566    JONES             7839  04/02/1981  2975    -   20 
7788    SCOTT   MANAGER   7566  12/09/1982  3000    -   20 
7902    FORD    MANAGER   7566  12/03/1981  3000    -   20 
7369    SMITH             7902  12/17/1980  800     -   20 
7876    ADAMS             7788  01/12/1983  1100    -   20 

So what will be the best way to write this query

Answer 1

Try:

UPDATE emp
   SET job = (CASE empno
                 WHEN 7788
                 THEN 'MANAGER'
                 WHEN 7902
                 THEN 'MANAGER'
                 ELSE NULL
               END)
 WHERE deptno = 20;

Or

UPDATE emp
   SET job = (CASE
                 WHEN empno IN (7788, 7902)
                 THEN 'MANAGER'
                 ELSE NULL
               END)
 WHERE deptno = 20;

Hope this is what you are after...

EDIT: After your comments about the input coming from a number table type something like this should work:

CREATE TYPE number_tab
AS TABLE OF NUMBER
/

Type Created.

CREATE OR REPLACE
PROCEDURE upd_emp (
   p_deptno    IN emp.deptno%TYPE,
   p_empno_tab IN number_tab
)
IS
BEGIN
   UPDATE emp e
      SET e.job = (SELECT (CASE 
                             WHEN t.column_value IS NULL
                             THEN NULL
                             ELSE 'MANAGER'
                            END)
                     FROM TABLE(p_empno_tab) t
                    WHERE t.column_value(+) = e.empno)
    WHERE deptno = p_deptno;
EXCEPTION
   WHEN others
   THEN
      ...Exception handling code
END upd_emp;
/