Oracle PL/SQL/Char Functions/NVL2 — различия между версиями

Материал из SQL эксперт
Перейти к: навигация, поиск
м (1 версия)
 
м (1 версия)
 
(нет различий)

Текущая версия на 09:58, 26 мая 2010

nvl2 with null value

  
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  );
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, null, "CLERK",     7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10);
1 row created.
SQL>
SQL>
SQL>  select e.ename, nvl2( e2.ename, "BACK TO WORK!", "NO BOSS!" ) "MGR"
  2      from emp e, emp e2
  3     where e.mgr = e2.empno(+)
  4    /
ENAME      MGR
---------- -------------
FORD       BACK TO WORK!
SCOTT      BACK TO WORK!
JAMES      BACK TO WORK!
TURNER     BACK TO WORK!
MARTIN     BACK TO WORK!
WARD       BACK TO WORK!
ALLEN      BACK TO WORK!
           BACK TO WORK!
ADAMS      BACK TO WORK!
CLARK      BACK TO WORK!
BLAKE      BACK TO WORK!
JONES      BACK TO WORK!
SMITH      BACK TO WORK!
KING       NO BOSS!
14 rows selected.
SQL>
SQL> drop table emp;
Table dropped.
SQL> --



NVL2(x, value1, value2): for string(char) value

 

SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ("01","Jason",    "Martin",  to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto",  "Programmer")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("02","Alison",   "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("03","James",    "Smith",   to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("04","Celia",    "Rice",    to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("05","Robert",   "Black",   to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("06","Linda",    "Green",   to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York",  "Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("07",NULL   ,    "Larry",   to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York",  "Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("08",NULL   ,    "Cat",     to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
  3  /
1 row created.
SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /
ID   FIRST_NAME LAST_NAME  START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- ---------- ---------- --------- --------- ---------- ---------- ---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison     Mathews    21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda      Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07              Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08              Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester
8 rows selected.
SQL>
SQL>
SQL> NVL2(x, value1, value2) returns value1 if x is not null. If x is null, value2 is returned.
SQL>
SQL> SELECT id, NVL2(first_name, "Known", "Unknown") FROM employee;
ID   NVL2(FI
---- -------
01   Known
02   Known
03   Known
04   Known
05   Known
06   Known
07   Unknown
08   Unknown
8 rows selected.
SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /
Table dropped.
SQL>
SQL>



NVL2(x, value1, value2):Returns value1 if x is not null; if x is null, value2 is returned

 

SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ("01","Jason",    "Martin",  to_date("19960725","YYYYMMDD"), to_date("20060725","YYYYMMDD"), 1234.56, "Toronto",  "Programmer")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("02","Alison",   "Mathews", to_date("19760321","YYYYMMDD"), to_date("19860221","YYYYMMDD"), 6661.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("03","James",    "Smith",   to_date("19781212","YYYYMMDD"), to_date("19900315","YYYYMMDD"), 6544.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("04","Celia",    "Rice",    to_date("19821024","YYYYMMDD"), to_date("19990421","YYYYMMDD"), 2344.78, "Vancouver","Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values("05","Robert",   "Black",   to_date("19840115","YYYYMMDD"), to_date("19980808","YYYYMMDD"), 2334.78, "Vancouver","Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("06",NULL,    "Green",   to_date("19870730","YYYYMMDD"), to_date("19960104","YYYYMMDD"), 4322.78,"New York",  "Tester")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("07","David",    "Larry",   to_date("19901231","YYYYMMDD"), to_date("19980212","YYYYMMDD"), 7897.78,"New York",  "Manager")
  3  /
1 row created.
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values("08",NULL,    "Cat",     to_date("19960917","YYYYMMDD"), to_date("20020415","YYYYMMDD"), 1232.78,"Vancouver", "Tester")
  3  /
1 row created.
SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /
ID   FIRST_NAME LAST_NAME  START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- ---------- ---------- --------- --------- ---------- ---------- ---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison     Mathews    21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06              Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David      Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08              Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester
8 rows selected.
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> NVL2(x, value1, value2):Returns value1 if x is not null; if x is null, value2 is returned.
SQL>
SQL> select NVL2(first_name, 0, 1) from employee;
NVL2(FIRST_NAME,0,1)
--------------------
                   0
                   0
                   0
                   0
                   0
                   1
                   0
                   1
8 rows selected.
SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /
Table dropped.
SQL>
SQL>



Use nvl2 to deal with null salary

 
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 ename, sal, comm
  2  ,      nvl2(comm,12*sal+comm,12*sal) as yearsal
  3  from   emp
  4  where  ename like "%T%";
Enter...
Tom         800  [N/A]    9600
Take       1500      0   18000
2 rows selected.
SQL> drop table emp;
Table dropped.