Use Decode as if statement to logic like 'if then else'

   
SQL>
SQL> CREATE TABLE EMP
  2  (EMPNO NUMBER(4) NOT NULL,
  3   ENAME VARCHAR2(10),
  4   JOB VARCHAR2(9),
  5   MGR NUMBER(4),
  6   HIREDATE DATE,
  7   SAL NUMBER(7, 2),
  8   COMM NUMBER(7, 2),
  9   DEPTNO NUMBER(2)
 10  );

Table created.

SQL>
SQL> INSERT INTO EMP VALUES (7369, 'SMITH',  'CLERK',     7902,TO_DATE('17-DEC-1980', 'DD-MON-YYYY'),  800, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7499, 'ALLEN',  'SALESMAN',  7698,TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600,  300, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7521, 'WARD',   'SALESMAN',  7698,TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250,  500, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7566, 'JONES',  'MANAGER',   7839,TO_DATE('2-APR-1981', 'DD-MON-YYYY'),  2975, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN',  7698,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7698, 'BLAKE',  'MANAGER',   7839,TO_DATE('1-MAY-1981', 'DD-MON-YYYY'),  2850, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7782, 'CLARK',  'MANAGER',   7839,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'),  2450, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7788, 'SCOTT',  'ANALYST',   7566,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7839, 'KING',   'PRESIDENT', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);

1 row created.

SQL> INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN',  7698,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'),  1500,    0, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7876, 'ADAMS',  'CLERK',     7788,TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7900, 'JAMES',  'CLERK',     7698,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'),   950, NULL, 30);

1 row created.

SQL> INSERT INTO EMP VALUES (7902, 'FORD',   'ANALYST',   7566,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'),  3000, NULL, 20);

1 row created.

SQL> INSERT INTO EMP VALUES (7934, 'KING', 'CLERK',     7782,TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);

1 row created.

SQL>
SQL> select * from emp;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 09-DEC-82       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 12-JAN-83       1100                    20
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 KING       CLERK           7782 23-JAN-82       1300                    10

14 rows selected.

SQL>
SQL> select decode( ename, 'KING', 'KING OF THE HILL', ename ) "ENAME"
  2  from emp;
ENAME
----------------
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING OF THE HILL
TURNER
ADAMS
JAMES
FORD
KING OF THE HILL

14 rows selected.

SQL>
SQL> drop table emp;

Table dropped.

SQL> --

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Use Decode as if statement to logic like 'if then else' : DECODE « Conversion Functions « Oracle PL / SQL

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