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oracle-databaseprocedure

Oracle conditional update query


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


Solution

  • 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;
    /