Oracle PL/SQL/Select Query/Case Query

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A searched CASE statement

   <source lang="sql">
  

SQL> BEGIN

 2    CASE TRUE
 3    WHEN (1 > 3) THEN
 4      dbms_output.put_line("One is greater than three.");
 5    WHEN (3 < 5) THEN
 6      dbms_output.put_line("Three is less than five.");
 7    WHEN (1 = 2) THEN
 8      dbms_output.put_line("One equals two.");
 9    ELSE
10      dbms_output.put_line("Nothing worked.");
11    END CASE;
12  END;
13  /

Three is less than five. PL/SQL procedure successfully completed. SQL>


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case switch based on clob data

   <source lang="sql">
  

SQL> declare

 2
 3    c1 clob := to_clob("abc");
 4    c2 clob;
 5
 6  begin
 7      case c1
 8           when to_clob("abc") then dbms_output.put_line("abc");
 9           when to_clob("def") then dbms_output.put_line("def");
10      end case;
11
12      c2 := case c1
13         when to_clob("abc") then "abc"
14         when to_clob("def") then "def"
15      end;
16
17      dbms_output.put_line(c2);
18
19  end;
20  /

abc abc PL/SQL procedure successfully completed. SQL>


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case when count(*) NOT between ... and

   <source lang="sql">
  

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  );

SQL> SQL> INSERT INTO EMP VALUES(7369, "SMITH", "CLERK", 7902,TO_DATE("17-DEC-1980", "DD-MON-YYYY"), 800, NULL, 20); SQL> INSERT INTO EMP VALUES(7499, "ALLEN", "SALESMAN", 7698,TO_DATE("20-FEB-1981", "DD-MON-YYYY"), 1600, 300, 30); SQL> INSERT INTO EMP VALUES(7521, "WARD", "SALESMAN", 7698,TO_DATE("22-FEB-1981", "DD-MON-YYYY"), 1250, 500, 30); SQL> INSERT INTO EMP VALUES(7566, "JONES", "MANAGER", 7839,TO_DATE("2-APR-1981", "DD-MON-YYYY"), 2975, NULL, 20); SQL> INSERT INTO EMP VALUES(7654, "MARTIN", "SALESMAN", 7698,TO_DATE("28-SEP-1981", "DD-MON-YYYY"), 1250, 1400, 30); SQL> INSERT INTO EMP VALUES(7698, "BLAKE", "MANAGER", 7839,TO_DATE("1-MAY-1981", "DD-MON-YYYY"), 2850, NULL, 30); SQL> INSERT INTO EMP VALUES(7782, "CLARK", "MANAGER", 7839,TO_DATE("9-JUN-1981", "DD-MON-YYYY"), 2450, NULL, 10); SQL> INSERT INTO EMP VALUES(7788, "SCOTT", "ANALYST", 7566,TO_DATE("09-DEC-1982", "DD-MON-YYYY"), 3000, NULL, 20); SQL> INSERT INTO EMP VALUES(7839, "KING", "PRESIDENT", NULL,TO_DATE("17-NOV-1981", "DD-MON-YYYY"), 5000, NULL, 10); SQL> INSERT INTO EMP VALUES(7844, "TURNER", "SALESMAN", 7698,TO_DATE("8-SEP-1981", "DD-MON-YYYY"), 1500, 0, 30); SQL> INSERT INTO EMP VALUES(7876, "ADAMS", "CLERK", 7788,TO_DATE("12-JAN-1983", "DD-MON-YYYY"), 1100, NULL, 20); SQL> INSERT INTO EMP VALUES(7900, "JAMES", "CLERK", 7698,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 950, NULL, 30); SQL> INSERT INTO EMP VALUES(7902, "FORD", "ANALYST", 7566,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 3000, NULL, 20); SQL> INSERT INTO EMP VALUES(7934, "MILLER", "CLERK", 7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10); SQL> SQL> SQL> select deptno, count(*),

 2         case when count(*) NOT between 3 and 8 then "..."
 3              else null
 4          end
 5    from emp
 6   group by deptno
 7  /
                                                             
   DEPTNO    COUNT(*)  CAS

---------- ---
       10           3
       20           5
       30           6
                   

SQL> delete from emp where empno in ( 7369, 7566, 7788 ); SQL> SQL> select deptno, count(*),

 2         case when count(*) NOT between 3 and 8 then "..."
 3              else null
 4          end
 5    from emp
 6   group by deptno
 7  /
                                                             
   DEPTNO    COUNT(*)  CAS

---------- ---
       10           3
       20           2  ...
       30           6

SQL> SQL> SQL> drop table emp;


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Combine Case with group by

   <source lang="sql">
  

SQL> -- create demo table SQL> create table Employee(

 2    empno              Number(3)  NOT NULL, -- Employee ID
 3    ename              VARCHAR2(10 BYTE),   -- Employee Name
 4    hireDate          DATE,                -- Date Employee Hired
 5    orig_salary        Number(8,2),         -- Orignal Salary
 6    curr_salary        Number(8,2),         -- Current Salary
 7    region             VARCHAR2(1 BYTE)     -- Region where employeed
 8  )
 9  /

Table created. SQL> SQL> create table job(

 2    empno              Number(3)  NOT NULL, -- Employee ID
 3    jobtitle           VARCHAR2(10 BYTE)    -- Employee job title
 4  )
 5  /

SQL> -- prepare data for employee table SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(122,"Alison",to_date("19960321","YYYYMMDD"), 45000,       48000,       "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(123, "James",to_date("19781212","YYYYMMDD"), 23000,       32000,       "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(104,"Celia",to_date("19821024","YYYYMMDD"), 53000,       58000,        "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(105,"Robert",to_date("19840115","YYYYMMDD"), 31000,      36000,        "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(116,"Linda", to_date("19870730","YYYYMMDD"), 43000,       53000,       "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(117,"David", to_date("19901231","YYYYMMDD"), 78000,       85000,       "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(108,"Jode",  to_date("19960917","YYYYMMDD"), 21000,       29000,       "E")
 3  /

1 row created. SQL> SQL> SQL> select * from employee;

    EMPNO ENAME      HIREDATE  ORIG_SALARY CURR_SALARY R

---------- --------- ----------- ----------- -
      122 Alison     21-MAR-96       45000       48000 E
      123 James      12-DEC-78       23000       32000 W
      104 Celia      24-OCT-82       53000       58000 E
      105 Robert     15-JAN-84       31000       36000 W
      116 Linda      30-JUL-87       43000       53000 E
      117 David      31-DEC-90       78000       85000 W
      108 Jode       17-SEP-96       21000       29000 E

7 rows selected. SQL> SQL> SELECT count(*),

 2    CASE region
 3      WHEN "N" then "North"
 4      WHEN "W" then "West"
 5      WHEN null then "Null"
 6    END Region -- CASE
 7  FROM employee
 8  GROUP BY region;
 COUNT(*) REGIO

-----
        3 West
        4

SQL> SQL> -- clean the table SQL> drop table Employee

 2  /

Table dropped. SQL> SQL>



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Combine case with NVL function

   <source lang="sql">
  

SQL> -- create demo table SQL> create table Employee(

 2    empno              Number(3)  NOT NULL, -- Employee ID
 3    ename              VARCHAR2(10 BYTE),   -- Employee Name
 4    hireDate          DATE,                -- Date Employee Hired
 5    orig_salary        Number(8,2),         -- Orignal Salary
 6    curr_salary        Number(8,2),         -- Current Salary
 7    region             VARCHAR2(1 BYTE)     -- Region where employeed
 8  )
 9  /

Table created. SQL> SQL> create table job(

 2    empno              Number(3)  NOT NULL, -- Employee ID
 3    jobtitle           VARCHAR2(10 BYTE)    -- Employee job title
 4  )
 5  /

SQL> -- prepare data for employee table SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(122,"Alison",to_date("19960321","YYYYMMDD"), 45000,       48000,       "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(123, "James",to_date("19781212","YYYYMMDD"), 23000,       32000,       "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(104,"Celia",to_date("19821024","YYYYMMDD"), 53000,       58000,        "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(105,"Robert",to_date("19840115","YYYYMMDD"), 31000,      36000,        "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(116,"Linda", to_date("19870730","YYYYMMDD"), 43000,       53000,       "E")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(117,"David", to_date("19901231","YYYYMMDD"), 78000,       85000,       "W")
 3  /

1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)

 2                values(108,"Jode",  to_date("19960917","YYYYMMDD"), 21000,       29000,       "E")
 3  /

1 row created. SQL> SQL> select * from employee;

    EMPNO ENAME      HIREDATE  ORIG_SALARY CURR_SALARY R

---------- --------- ----------- ----------- -
      122 Alison     21-MAR-96       45000       48000 E
      123 James      12-DEC-78       23000       32000 W
      104 Celia      24-OCT-82       53000       58000 E
      105 Robert     15-JAN-84       31000       36000 W
      116 Linda      30-JUL-87       43000       53000 E
      117 David      31-DEC-90       78000       85000 W
      108 Jode       17-SEP-96       21000       29000 E

7 rows selected. SQL> SQL> SELECT count(*),

 2    CASE NVL(region,"x")
 3      WHEN "x" then "Null"
 4      ELSE region
 5      END Region -- CASE
 6  FROM employee
 7  GROUP BY region;
 COUNT(*) REGI

----
        3 W
        4 E

SQL> SQL> -- clean the table SQL> drop table Employee

 2  /

Table dropped. SQL> SQL> SQL>



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Rename case when column

   <source lang="sql">
  

SQL> SQL> create table emp

 2  ( empno      NUMBER(4)    constraint E_PK  primary key
 3  , ename      VARCHAR2(8)
 4  , init       VARCHAR2(5)
 5  , job        VARCHAR2(8)
 6  , mgr        NUMBER(4)
 7  , bdate      DATE
 8  , sal       NUMBER(6,2)
 9  , comm       NUMBER(6,2)
10  , deptno     NUMBER(2)    default 10
11  ) ;

Table created. SQL> insert into emp values(1,"Tom","N", "Coder", 13,date "1965-12-17", 800 , NULL, 20); 1 row created. SQL> insert into emp values(2,"Jack","JAM", "Tester",6,date "1961-02-20", 1600, 300, 30); 1 row created. SQL> insert into emp values(3,"Wil","TF", "Tester",6,date "1962-02-22", 1250, 500, 30); 1 row created. SQL> insert into emp values(4,"Jane","JM", "Designer", 9,date "1967-04-02", 2975, NULL, 20); 1 row created. SQL> insert into emp values(5,"Mary","P", "Tester",6,date "1956-09-28", 1250, 1400, 30); 1 row created. SQL> insert into emp values(6,"Black","R", "Designer", 9,date "1963-11-01", 2850, NULL, 30); 1 row created. SQL> SQL> select ename, job

 2  ,      case when job   = "Coder" then "  10%"
 3              when job   = "Designer" then "  20%"
 4              when ename = "Tom"   then "  30%"
 5                                     else "   0%"
 6         end  as raise
 7  from   emp
 8  order  by raise desc, ename;

ENAME JOB RAISE


-------- -----

Black Designer 20% Jane Designer 20% Tom Coder 10% Jack Tester 0% Mary Tester 0% Wil Tester 0% 6 rows selected. SQL> SQL> SQL> drop table emp; Table dropped.


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Use case when and grouping function together

   <source lang="sql">
  

SQL> SQL> create table emp

 2  ( empno      NUMBER(4)    constraint E_PK primary key
 3  , ename      VARCHAR2(8)
 4  , init       VARCHAR2(5)
 5  , job        VARCHAR2(8)
 6  , mgr        NUMBER(4)
 7  , bdate      DATE
 8  , sal       NUMBER(6,2)
 9  , comm       NUMBER(6,2)
10  , deptno     NUMBER(2)    default 10
11  ) ;

Table created. SQL> insert into emp values(1,"Tom","N", "TRAINER", 13,date "1965-12-17", 800 , NULL, 20); 1 row created. SQL> insert into emp values(2,"Jack","JAM", "Tester",6,date "1961-02-20", 1600, 300, 30); 1 row created. SQL> insert into emp values(3,"Wil","TF" , "Tester",6,date "1962-02-22", 1250, 500, 30); 1 row created. SQL> insert into emp values(4,"Jane","JM", "Designer", 9,date "1967-04-02", 2975, NULL, 20); 1 row created. SQL> insert into emp values(5,"Mary","P", "Tester",6,date "1956-09-28", 1250, 1400, 30); 1 row created. SQL> insert into emp values(6,"Black","R", "Designer", 9,date "1963-11-01", 2850, NULL, 30); 1 row created. SQL> insert into emp values(7,"Chris","AB", "Designer", 9,date "1965-06-09", 2450, NULL, 10); 1 row created. SQL> insert into emp values(8,"Smart","SCJ", "TRAINER", 4,date "1959-11-26", 3000, NULL, 20); 1 row created. SQL> insert into emp values(9,"Peter","CC", "Designer",NULL,date "1952-11-17", 5000, NULL, 10); 1 row created. SQL> insert into emp values(10,"Take","JJ", "Tester",6,date "1968-09-28", 1500, 0, 30); 1 row created. SQL> insert into emp values(11,"Ana","AA", "TRAINER", 8,date "1966-12-30", 1100, NULL, 20); 1 row created. SQL> insert into emp values(12,"Jane","R", "Manager", 6,date "1969-12-03", 800 , NULL, 30); 1 row created. SQL> insert into emp values(13,"Fake","MG", "TRAINER", 4,date "1959-02-13", 3000, NULL, 20); 1 row created. SQL> insert into emp values(14,"Mike","TJA","Manager", 7,date "1962-01-23", 1300, NULL, 10); 1 row created. SQL> SQL> select deptno

 2  ,        case grouping(job)
 3                when 0 then job
 4                when 1 then "total"
 5           end  job
 6  ,        count(empno) headcount
 7  from     emp
 8  group by ROLLUP(deptno, job);
   DEPTNO JOB       HEADCOUNT

-------- ----------
       10 Manager           1
       10 Designer          2
       10 total             3
       20 TRAINER           4
       20 Designer          1
       20 total             5
       30 Tester            4
       30 Manager           1
       30 Designer          1
       30 total             6
          total            14

11 rows selected. SQL> SQL> SQL> drop table emp; Table dropped. SQL>


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Use case when clause to decode value

   <source lang="sql">
  

SQL> create table registrations

 2  ( attendee    NUMBER(4)
 3  , course      VARCHAR2(6)
 4  , begindate   DATE
 5  , evaluation  NUMBER(1)
 6  , constraint  R_PK        primary key (attendee,course,begindate)
 7  ) ;

Table created. SQL> SQL> insert into registrations values (2,"SQL",date "2009-04-12",4 ); 1 row created. SQL> insert into registrations values (14,"SQL",date "2009-04-12",5 ); 1 row created. SQL> insert into registrations values (6,"SQL",date "2009-04-12",4 ); 1 row created. SQL> insert into registrations values (11,"SQL",date "2009-04-12",2 ); 1 row created. SQL> insert into registrations values (8,"SQL",date "2009-10-04",NULL); 1 row created. SQL> insert into registrations values (9,"SQL",date "2009-10-04",3 ); 1 row created. SQL> insert into registrations values (13,"SQL",date "2009-10-04",4 ); 1 row created. SQL> insert into registrations values (13,"SQL",date "2009-12-13",NULL); 1 row created. SQL> insert into registrations values (6,"SQL",date "2009-12-13",NULL); 1 row created. SQL> insert into registrations values (3,"OAU",date "2009-08-10",4 ); 1 row created. SQL> insert into registrations values (12,"OAU",date "2009-08-10",4 ); 1 row created. SQL> insert into registrations values (13,"OAU",date "2009-08-10",5 ); 1 row created. SQL> SQL> select attendee, begindate

 2  ,      case evaluation
 3              when 1 then "bad"
 4              when 2 then "mediocre"
 5              when 3 then "ok"
 6              when 4 then "good"
 7              when 5 then "excellent"
 8                     else "not filled in"
 9         end
10  from   registrations
11  where  course = "SQL";
 ATTENDEE BEGINDATE  CASEEVALUATIO

---------- -------------
        2 12-04-2009 good
       14 12-04-2009 excellent
        6 12-04-2009 good
       11 12-04-2009 mediocre
        8 04-10-2009 not filled in
        9 04-10-2009 ok
       13 04-10-2009 good
       13 13-12-2009 not filled in
        6 13-12-2009 not filled in

9 rows selected. SQL> SQL> SQL> drop table registrations; Table dropped.


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Use case when statement to replace if statement

   <source lang="sql">
  

SQL> SQL> create or replace procedure searched_case(p1 in number) is

 2     v_switch char(1);
 3  BEGIN
 4     v_switch :=
 5     CASE
 6       WHEN p1 = 1 THEN "A"
 7       WHEN p1 = 2 THEN "B"
 8       WHEN p1 = 3 THEN "C"
 9     END;
10     dbms_output.put_line(v_switch);
11  END;
12  /

Procedure created. SQL> SQL>


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Use case when statement with between ... and

   <source lang="sql">
  

SQL> SQL> create table emp(

 2            emp_no                 integer         primary key
 3           ,lastname               varchar2(20)    not null
 4           ,firstname              varchar2(15)    not null
 5           ,midinit                varchar2(1)
 6           ,street                 varchar2(30)
 7           ,city                   varchar2(20)
 8           ,state                  varchar2(2)
 9           ,zip                    varchar2(5)
10           ,shortZipCode           varchar2(4)
11           ,area_code              varchar2(3)
12           ,phone                  varchar2(8)
13           ,salary                 number(5,2)
14            ,birthdate              date
15           ,startDate              date
16           ,title                  varchar2(20)
17           ,dept_no                integer
18           ,mgr                    integer
19           ,region                 number
20           ,division               number
21           ,total_sales            number
22    );

Table created. SQL> SQL> SQL> SQL> SQL> -- emp Table Inserts: SQL> insert into emp(emp_no, lastname, firstname, midinit, street, city, state, zip,shortZipCode, area_code, phone, birthdate, title)values

 2                       (1,"Z","Joy","R","1 Ave","New York","NY","12122","2333","212","200-1111","12-nov-1976","President");

1 row created. SQL> SQL> SQL> SQL> SQL> create table avg_sal

 2   as select avg(salary) AS avg_Sal from emp;

Table created. SQL> SQL> SQL> select

 2   case when salary between 6 and 8 then "6-8"
 3        when salary in (9,10)       then "9-10"
 4        when exists (select null from avg_sal where avg_sal = salary)
 5                                    then "EXISTS"
 6        when to_char(salary) like "2%" then "Like2"
 7        when salary is null then "Null"
 8        else "ELSE Empno: "|| emp_no
 9        end
10        AS case_test
11   from emp
12   /

CASE_TEST


Null SQL> SQL> SQL> drop table avg_sal; Table dropped. SQL> SQL> drop table emp; Table dropped. SQL> SQL> SQL>


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Use case when statement with exists and subquery

   <source lang="sql">
  

SQL> SQL> create table emp(

 2            emp_no                 integer         primary key
 3           ,lastname               varchar2(20)    not null
 4           ,firstname              varchar2(15)    not null
 5           ,midinit                varchar2(1)
 6           ,street                 varchar2(30)
 7           ,city                   varchar2(20)
 8           ,state                  varchar2(2)
 9           ,zip                    varchar2(5)
10           ,shortZipCode           varchar2(4)
11           ,area_code              varchar2(3)
12           ,phone                  varchar2(8)
13           ,salary                 number(5,2)
14            ,birthdate              date
15           ,startDate              date
16           ,title                  varchar2(20)
17           ,dept_no                integer
18           ,mgr                    integer
19           ,region                 number
20           ,division               number
21           ,total_sales            number
22    );

Table created. SQL> SQL> SQL> SQL> SQL> -- emp Table Inserts: SQL> insert into emp(emp_no, lastname, firstname, midinit, street, city, state, zip,shortZipCode, area_code, phone, birthdate, title)values

 2                       (1,"Z","Joy","R","1 Ave","New York","NY","12122","2333","212","200-1111","12-nov-1976","President");

1 row created. SQL> SQL> SQL> SQL> SQL> create table avg_sal

 2   as select avg(salary) AS avg_Sal from emp;

Table created. SQL> SQL> SQL> select

 2   case when salary between 6 and 8 then "6-8"
 3        when salary in (9,10)       then "9-10"
 4        when exists (select null from avg_sal where avg_sal = salary)
 5                                    then "EXISTS"
 6        when to_char(salary) like "2%" then "Like2"
 7        when salary is null then "Null"
 8        else "ELSE Empno: "|| emp_no
 9        end
10        AS case_test
11   from emp
12   /

CASE_TEST


Null SQL> SQL> SQL> drop table avg_sal; Table dropped. SQL> SQL> drop table emp; Table dropped. SQL> SQL> SQL>


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Use case when statement with in()

   <source lang="sql">
  

SQL> SQL> create table emp(

 2            emp_no                 integer         primary key
 3           ,lastname               varchar2(20)    not null
 4           ,firstname              varchar2(15)    not null
 5           ,midinit                varchar2(1)
 6           ,street                 varchar2(30)
 7           ,city                   varchar2(20)
 8           ,state                  varchar2(2)
 9           ,zip                    varchar2(5)
10           ,shortZipCode           varchar2(4)
11           ,area_code              varchar2(3)
12           ,phone                  varchar2(8)
13           ,salary                 number(5,2)
14            ,birthdate              date
15           ,startDate              date
16           ,title                  varchar2(20)
17           ,dept_no                integer
18           ,mgr                    integer
19           ,region                 number
20           ,division               number
21           ,total_sales            number
22    );

Table created. SQL> SQL> SQL> SQL> SQL> -- emp Table Inserts: SQL> insert into emp(emp_no, lastname, firstname, midinit, street, city, state, zip,shortZipCode, area_code, phone, birthdate, title)values

 2                       (1,"Z","Joy","R","1 Ave","New York","NY","12122","2333","212","200-1111","12-nov-1976","President");

1 row created. SQL> SQL> SQL> SQL> SQL> create table avg_sal

 2   as select avg(salary) AS avg_Sal from emp;

Table created. SQL> SQL> SQL> select

 2   case when salary between 6 and 8 then "6-8"
 3        when salary in (9,10)       then "9-10"
 4        when exists (select null from avg_sal where avg_sal = salary)
 5                                    then "EXISTS"
 6        when to_char(salary) like "2%" then "Like2"
 7        when salary is null then "Null"
 8        else "ELSE Empno: "|| emp_no
 9        end
10        AS case_test
11   from emp
12   /

CASE_TEST


Null SQL> SQL> SQL> drop table avg_sal; Table dropped. SQL> SQL> drop table emp; Table dropped. SQL> SQL> SQL>


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Use case when statement with to_char() like

   <source lang="sql">
  

SQL> SQL> create table emp(

 2            emp_no                 integer         primary key
 3           ,lastname               varchar2(20)    not null
 4           ,firstname              varchar2(15)    not null
 5           ,midinit                varchar2(1)
 6           ,street                 varchar2(30)
 7           ,city                   varchar2(20)
 8           ,state                  varchar2(2)
 9           ,zip                    varchar2(5)
10           ,shortZipCode           varchar2(4)
11           ,area_code              varchar2(3)
12           ,phone                  varchar2(8)
13           ,salary                 number(5,2)
14            ,birthdate              date
15           ,startDate              date
16           ,title                  varchar2(20)
17           ,dept_no                integer
18           ,mgr                    integer
19           ,region                 number
20           ,division               number
21           ,total_sales            number
22    );

Table created. SQL> SQL> SQL> SQL> SQL> -- emp Table Inserts: SQL> insert into emp(emp_no, lastname, firstname, midinit, street, city, state, zip,shortZipCode, area_code, phone, birthdate, title)values

 2                       (1,"Z","Joy","R","1 Ave","New York","NY","12122","2333","212","200-1111","12-nov-1976","President");

1 row created. SQL> SQL> SQL> SQL> SQL> create table avg_sal

 2   as select avg(salary) AS avg_Sal from emp;

Table created. SQL> SQL> SQL> select

 2   case when salary between 6 and 8 then "6-8"
 3        when salary in (9,10)       then "9-10"
 4        when exists (select null from avg_sal where avg_sal = salary)
 5                                    then "EXISTS"
 6        when to_char(salary) like "2%" then "Like2"
 7        when salary is null then "Null"
 8        else "ELSE Empno: "|| emp_no
 9        end
10        AS case_test
11   from emp
12   /

CASE_TEST


Null SQL> SQL> SQL> drop table avg_sal; Table dropped. SQL> SQL> drop table emp; Table dropped. SQL> SQL> SQL>


 </source>
   
  


use case when to control the order index

   <source lang="sql">
  

SQL> SQL> SQL> create table emp

 2  ( empno      NUMBER(4)    constraint E_PK primary key
 3  , ename      VARCHAR2(8)
 4  , init       VARCHAR2(5)
 5  , job        VARCHAR2(8)
 6  , mgr        NUMBER(4)
 7  , bdate      DATE
 8  , sal        NUMBER(6,2)
 9  , comm       NUMBER(6,2)
10  , deptno     NUMBER(2)    default 10
11  ) ;

Table created. SQL> insert into emp values(1,"Tom","N", "TRAINER", 13,date "1965-12-17", 800 , NULL, 20); 1 row created. SQL> insert into emp values(2,"Jack","JAM", "Tester",6,date "1961-02-20", 1600, 300, 30); 1 row created. SQL> insert into emp values(3,"Wil","TF" , "Tester",6,date "1962-02-22", 1250, 500, 30); 1 row created. SQL> insert into emp values(4,"Jane","JM", "Designer", 9,date "1967-04-02", 2975, NULL, 20); 1 row created. SQL> insert into emp values(5,"Mary","P", "Tester",6,date "1956-09-28", 1250, 1400, 30); 1 row created. SQL> insert into emp values(6,"Black","R", "Designer", 9,date "1963-11-01", 2850, NULL, 30); 1 row created. SQL> insert into emp values(7,"Chris","AB", "Designer", 9,date "1965-06-09", 2450, NULL, 10); 1 row created. SQL> insert into emp values(8,"Smart","SCJ", "TRAINER", 4,date "1959-11-26", 3000, NULL, 20); 1 row created. SQL> insert into emp values(9,"Peter","CC", "Designer",NULL,date "1952-11-17", 5000, NULL, 10); 1 row created. SQL> insert into emp values(10,"Take","JJ", "Tester",6,date "1968-09-28", 1500, 0, 30); 1 row created. SQL> insert into emp values(11,"Ana","AA", "TRAINER", 8,date "1966-12-30", 1100, NULL, 20); 1 row created. SQL> insert into emp values(12,"Jane","R", "Manager", 6,date "1969-12-03", 800 , NULL, 30); 1 row created. SQL> insert into emp values(13,"Fake","MG", "TRAINER", 4,date "1959-02-13", 3000, NULL, 20); 1 row created. SQL> insert into emp values(14,"Mike","TJA","Manager", 7,date "1962-01-23", 1300, NULL, 10); 1 row created. SQL> select job, ename

 2  ,      case
 3           when sal <= 2500
 4           then "cheap"
 5           else "expensive"
 6         end         as class
 7  from   emp
 8  where  bdate < date "1964-01-01"
 9  order  by case job
10            when "Designer" then 1
11            when "Designer"  then 2
12                            else 3
13            end;

Enter... Designer Black expensive Designer Peter expensive Tester Mary cheap Manager Mike cheap TRAINER Smart expensive TRAINER Fake expensive Tester Wil cheap Tester Jack cheap 8 rows selected. SQL> SQL> drop table emp; Table dropped. SQL>


 </source>
   
  


Use case ... when to output comments for marks

   <source lang="sql">
  

SQL> SQL> SQL> CREATE TABLE empExam (

 2     empID  INT NOT NULL,
 3     ExamID     INT NOT NULL,
 4     Mark       INT,
 5     Taken   SMALLINT,
 6     Comments   VARCHAR(255),
 7     CONSTRAINT PK_empExam PRIMARY KEY (empID, ExamID));

Table created. SQL> SQL> SQL> INSERT INTO empExam (empID,ExamID,Mark,Taken,Comments) VALUES (1,1,55,1,"Satisfactory"); 1 row created. SQL> INSERT INTO empExam (empID,ExamID,Mark,Taken,Comments) VALUES (1,2,73,1,"Good result"); 1 row created. SQL> INSERT INTO empExam (empID,ExamID,Mark,Taken,Comments) VALUES (2,3,44,1,"Hard"); 1 row created. SQL> INSERT INTO empExam (empID,ExamID,Mark,Taken,Comments) VALUES (2,5,39,0,"Simple"); 1 row created. SQL> INSERT INTO empExam (empID,ExamID,Mark,Taken) VALUES (2,6,63,1); 1 row created. SQL> SQL> CREATE OR REPLACE PROCEDURE GetempComments(i_empID IN INT,o_Comments OUT VARCHAR)

 2  AS
 3     exams_sat    INT;
 4     avg_mark     INT;
 5     tmp_comments VARCHAR(100);
 6  BEGIN
 7  SELECT COUNT(ExamID) INTO exams_sat FROM empExam
 8     WHERE empID = i_empID;
 9  IF exams_sat = 0 THEN
10     tmp_comments := "n/a - this emp sat no exams";
11  ELSE
12     SELECT AVG(Mark) INTO avg_mark FROM empExam
13     WHERE empID = i_empID;
14     CASE
15        WHEN avg_mark < 50 THEN tmp_comments := "Poor";
16        WHEN avg_mark < 60 THEN tmp_comments := "Adequate.";
17        WHEN avg_mark < 70 THEN tmp_comments := "Satisfactory.";
18        ELSE tmp_comments := "Excellent!";
19     END CASE;
20  END IF;
21  o_Comments := tmp_comments;
22  END;
23  /

SP2-0804: Procedure created with compilation warnings SQL> SET SERVEROUT ON SQL> DECLARE

 2     comments VARCHAR(100);
 3  BEGIN
 4     GetempComments(2, comments);
 5     dbms_output.put_line(comments);
 6  END;
 7  /

Poor PL/SQL procedure successfully completed. SQL> SQL> SQL> drop table empExam; Table dropped.


 </source>
   
  


Use case when with comparasion operator

   <source lang="sql">
  

SQL> SQL> create table emp(

 2            emp_no                 integer         primary key
 3           ,lastname               varchar2(20)    not null
 4           ,firstname              varchar2(15)    not null
 5           ,midinit                varchar2(1)
 6           ,street                 varchar2(30)
 7           ,city                   varchar2(20)
 8           ,state                  varchar2(2)
 9           ,zip                    varchar2(5)
10           ,shortZipCode                  varchar2(4)
11           ,area_code              varchar2(3)
12           ,phone                  varchar2(8)
13           ,salary                 number(5,2)
14            ,birthdate              date
15           ,startDate               date
16           ,title                  varchar2(20)
17           ,dept_no                integer
18           ,mgr                    integer
19           ,region                 number
20           ,division               number
21           ,total_sales            number
22    );

Table created. SQL> SQL> SQL> SQL> SQL> SQL> create table avg_sal

 2   as select avg(salary) AS avg_Sal from emp;

Table created. SQL> SQL> select lastname, salary,

 2   CASE WHEN salary > avg_sal THEN "> Average of " || to_char(avg_sal, "99.99")
 3        WHEN salary < avg_sal THEN "< Average of " || to_char(avg_sal, "99.99")
 4        ELSE "= Average of " || to_char(avg_sal, "99.99")
 5        END
 6   from emp, avg_sal
 7   /

no rows selected SQL> SQL> drop table emp; Table dropped. SQL> SQL> SQL> SQL> SQL> drop table avg_Sal; Table dropped. SQL>


 </source>
   
  


Use the CASE expression and SUM function

   <source lang="sql">
   

SQL> SQL> SQL> create table employee(

 2           emp_no                 integer         primary key
 3          ,lastname               varchar2(20)    not null
 4          ,firstname              varchar2(15)    not null
 5          ,midinit                varchar2(1)
 6          ,street                 varchar2(30)
 7          ,city                   varchar2(20)
 8          ,state                  varchar2(2)
 9          ,zip                    varchar2(5)
10          ,zip_4                  varchar2(4)
11          ,area_code              varchar2(3)
12          ,phone                  varchar2(8)
13          ,salary                 number(3)
14          ,birthdate              date
15          ,hiredate               date
16          ,title                  varchar2(20)
17          ,dept_no                integer
18          ,mgr                    integer
19          ,region                 number
20          ,division               number
21          ,total_sales            number
22  );

Table created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (1,"Anderson","Nancy","N","33 Ave","London","NY","11111","1111","212","234-1111",3.75,"21-mar-1927","1-feb-1947","Sales Manager",2,null,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (2,"Last","First","F","12 Ave","Paris","CA","22222","2222","223","867-2222",7.75,"14-feb-1976","15-mar-1985","Sales Clerk",2,1,100,10,10000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (3,"Wash","Georgia","G","1 Street14","Barton","NJ","33333","3333","214","340-3333",11.50,"2-jul-1977","21-apr-2004","Designer",1,2,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (4,"Bush","Dave","D","56 Street","Island","RI","44444","4444","215","777-4444",21.65,"15-may-1945","2-aug-1975","Designer",1,2,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (5,"Will","Robin","W","56 Street","Island","MA","55555","5555","216","777-5555",24.65,"10-dec-1980","2-aug-2007","Designer",1,5,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (6,"Pete","Mona","M","13 Ave","York","MO","66666","6666","217","111-6666",9,"14-feb-1966","15-mar-1985","Sales Clerk",2,5,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (7,"Roke","John","J","67 Ave","New York","BC","77777","7777","218","122-7777",10.00,"14-jun-1955","15-mar-1975","Accountant",3,2,100,10,40000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2               values (8,"Horry","Tedi","T","1236 Lane","Newton","NY","88888","8888","219","222-8888",13.00,"10-jun-1955","15-aug-1985","Sales Representative",3,2,100,10,50000);

1 row created. SQL> insert into employee(emp_no, lastname, firstname, midinit, street, city, state, zip,zip_4, area_code, phone, salary, birthdate, hiredate,title, dept_no, mgr, region, division, total_sales)

 2                values (9,"Bar","Candi","C","400 East Street","Yorken","NY","99999","9999","220","321-9999",12.00,"10-oct-1933","15-jan-1969","Sales Representative",3,5,100,10,35000);

1 row created. SQL> SQL> select * from employee;

   EMP_NO LASTNAME             FIRSTNAME       M STREET                         CITY                 ST ZIP   ZIP_ ARE PHONE        SALARY

-------------------- --------------- - ------------------------------ -------------------- -- ----- ---- --- -------- ----------

BIRTHDATE HIREDATE TITLE DEPT_NO MGR REGION DIVISION TOTAL_SALES


-------------------- -------------------- ---------- ---------- ---------- ---------- -----------
        1 Anderson             Nancy           N 33 Ave                         London               NY 11111 1111 212 234-1111          4

21-MAR-1927 00:00:00 01-FEB-1947 00:00:00 Sales Manager 2 100 10 40000

        2 Last                 First           F 12 Ave                         Paris                CA 22222 2222 223 867-2222          8

14-FEB-1976 00:00:00 15-MAR-1985 00:00:00 Sales Clerk 2 1 100 10 10000

        3 Wash                 Georgia         G 1 Street14                     Barton               NJ 33333 3333 214 340-3333         12

02-JUL-1977 00:00:00 21-APR-2004 00:00:00 Designer 1 2 100 10 40000

        4 Bush                 Dave            D 56 Street                      Island               RI 44444 4444 215 777-4444         22

15-MAY-1945 00:00:00 02-AUG-1975 00:00:00 Designer 1 2 100 10 40000

        5 Will                 Robin           W 56 Street                      Island               MA 55555 5555 216 777-5555         25

10-DEC-1980 00:00:00 02-AUG-2007 00:00:00 Designer 1 5 100 10 40000

        6 Pete                 Mona            M 13 Ave                         York                 MO 66666 6666 217 111-6666          9

14-FEB-1966 00:00:00 15-MAR-1985 00:00:00 Sales Clerk 2 5 100 10 40000

        7 Roke                 John            J 67 Ave                         New York             BC 77777 7777 218 122-7777         10

14-JUN-1955 00:00:00 15-MAR-1975 00:00:00 Accountant 3 2 100 10 40000

        8 Horry                Tedi            T 1236 Lane                      Newton               NY 88888 8888 219 222-8888         13

10-JUN-1955 00:00:00 15-AUG-1985 00:00:00 Sales Representative 3 2 100 10 50000

        9 Bar                  Candi           C 400 East Street                Yorken               NY 99999 9999 220 321-9999         12

10-OCT-1933 00:00:00 15-JAN-1969 00:00:00 Sales Representative 3 5 100 10 35000

9 rows selected. SQL> SQL> select dept_no, title,

 2         case
 3         when upper(title) like "%SALES%" then sum(salary)
 4         when upper(title) = "ACCOUNTANT" then sum(salary)
 5         when upper(title) = "DESIGNER" then sum(salary)
 6         end AS sum_salary
 7  FROM EMPLOYEE
 8  GROUP BY dept_no, title;
  DEPT_NO TITLE                SUM_SALARY

-------------------- ----------
        2 Sales Clerk                  17
        1 Designer                     59
        3 Sales Representative         25
        2 Sales Manager                 4
        3 Accountant                   10

5 rows selected. SQL> SQL> SQL> drop table employee; Table dropped. SQL> --


 </source>
   
  


Use the CASE expression and SUM function to create an order price report

   <source lang="sql">
   

SQL> SQL> SQL> create table ord(

 2           order_no               integer          primary key
 3          ,cust_no                integer
 4          ,order_date             date not null
 5          ,total_order_price      number(7,2)
 6          ,deliver_date           date
 7          ,deliver_time           varchar2(7)
 8          ,payment_method         varchar2(2)
 9          ,emp_no                 number(3,0)
10          ,deliver_name           varchar2(35)
11          ,gift_message           varchar2(100)
12  );

Table created. SQL> SQL> SQL> insert into ord(order_no,cust_no,order_date,total_order_price,deliver_date,deliver_time,payment_method,emp_no,deliver_name,gift_message)

 2           values(1,1,"14-Feb-2002", 23.00, "14-Feb-2002", "12 noon", "CA",1, null, "Gift for wife");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time ,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(2,1,"14-Feb-2003", 510.98, "14-feb-2003", "5 pm", "NY",7, "Rose Ted", "Happy Valentines Day to Mother");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(3, 2,"14-Feb-2004", 315.99, "14-feb-2004", "3 pm", "VS",2, "Ani Forest", "Happy Valentines Day to Father");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(4, 2,"14-Feb-1999", 191.95, "14-feb-1999", "2 pm", "NJ",2, "O. John", "Happy Valentines Day");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(5, 6,"4-mar-2002", 101.95, "5-mar-2002", "2:30 pm", "MO"   , 2, "Cora", "Happy Birthday from John");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(6, 9,"7-apr-2003", 221.95, "7-apr-2003", "3 pm", "MA", 2, "Sake Keith", "Happy Birthday from Joe" );

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(7, 9,"20-jun-2004", 315.95, "21-jun-2004", "12 noon", "BC", 2, "Jessica Li", "Happy Birthday from Jessica");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values (8, 12, "31-dec-1999", 135.95, "1-jan-2000", "12 noon", "DI",      3, "Larry", "Happy New Year from Lawrence");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values (9, 12, "26-dec-2003", 715.95, "2-jan-2004", "12 noon", "SK",7, "Did", "Happy Birthday from Nancy" );

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(10, 4, sysdate-1, 119.95, sysdate+2, "6:30 pm", "VG",2, "P. Jing", "Happy Valentines Day to Jason");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )

 2           values(11, 2, sysdate, 310.00, sysdate+2, "3:30 pm", "DC",2, "C. Late", "Happy Birthday Day to Jack");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)

 2           values(12, 7, sysdate-3, 121.95, sysdate-2, "1:30 pm", "AC",2, "W. Last", "Happy Birthday Day to You");

1 row created. SQL> insert into ord(order_no ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)

 2           values(13, 7, sysdate, 211.95, sysdate-4, "4:30 pm", "CA",2, "J. Bond", "Thanks for hard working");

1 row created. SQL> SQL> select payment_method from ord; PA -- CA NY VS NJ MO MA BC DI SK VG DC AC CA 13 rows selected. SQL> SQL> select case payment_method when "CA" then "CASH"

 2                             when "DI" then "DISCOVER"
 3                             when "VG" then "VISA GOLD"
 4                             when "VS" then "VISA STANDARD"
 5                             when "AX" then "AMEX"
 6                             ELSE "OTHER"
 7         END AS pay_method,
 8         sum( case when total_order_price < 30 then 1 else 0 end) AS Small_Order,
 9         sum( case when total_order_price = 30 then 1 else 0 end) AS Medium_Order,
10         sum( case when total_order_price > 30 then 1 else 0 end) AS Large_Order
11  from ord
12  group by payment_method
13  /

PAY_METHOD SMALL_ORDER MEDIUM_ORDER LARGE_ORDER


----------- ------------ -----------

VISA STANDARD 0 0 1 OTHER 0 0 1 CASH 1 0 1 OTHER 0 0 1 OTHER 0 0 1 DISCOVER 0 0 1 VISA GOLD 0 0 1 OTHER 0 0 1 OTHER 0 0 1 OTHER 0 0 1 OTHER 0 0 1 OTHER 0 0 1 12 rows selected. SQL> SQL> drop table ord; Table dropped. SQL> --


 </source>
   
  


You could use the case statement in an SQL statement

   <source lang="sql">
  

SQL> SQL> SQL> -- You could use the case statement in an SQL statement as follows: SQL> SQL> select table_name,

 2      CASE owner
 3      WHEN "SYS" THEN "The owner is SYS"
 4      WHEN "SYSTEM" THEN "The owner is SYSTEM"
 5      ELSE "The owner is another value" END
 6      from all_tables
 7      where rownum<200;

TABLE_NAME CASEOWNERWHEN"SYS"THEN"THE


--------------------------

CON$ The owner is SYS RULESET$ The owner is SYS INDPART_PARAM$ The owner is SYS OL$ The owner is another value OL$HINTS The owner is another value OL$NODES The owner is another value SQL$ The owner is SYS SQL$TEXT The owner is SYS SQLPROF$ The owner is SYS SQLPROF$DESC The owner is SYS SQL> SQL>



 </source>