Oracle PL/SQL/Table Joins/Cartesian product — различия между версиями
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Версия 13:45, 26 мая 2010
Cartesian Products in action
SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
2 ENAME VARCHAR2(10),
3 JOB VARCHAR2(9),
4 MGR NUMBER(4),
5 HIREDATE DATE,
6 SAL NUMBER(7, 2),
7 COMM NUMBER(7, 2),
8 DEPTNO NUMBER(2));
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, "MILLER", "CLERK", 7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10);
1 row created.
SQL>
SQL> CREATE TABLE DEPT (DEPTNO NUMBER(2),DNAME VARCHAR2(14),LOC VARCHAR2(13) );
Table created.
SQL>
SQL> INSERT INTO DEPT VALUES (10, "ACCOUNTING", "NEW YORK");
1 row created.
SQL> INSERT INTO DEPT VALUES (20, "RESEARCH", "DALLAS");
1 row created.
SQL> INSERT INTO DEPT VALUES (30, "SALES", "CHICAGO");
1 row created.
SQL> INSERT INTO DEPT VALUES (40, "OPERATIONS", "BOSTON");
1 row created.
SQL>
SQL>
SQL>
SQL> -- Cartesian Products
SQL>
SQL> SELECT e.empno, d.deptno FROM emp e, dept d;
EMPNO DEPTNO
---------- ----------
7369 10
7499 10
7521 10
7566 10
7654 10
7698 10
7782 10
7788 10
7839 10
7844 10
7876 10
7900 10
7902 10
7934 10
7369 20
7499 20
7521 20
7566 20
7654 20
7698 20
7782 20
7788 20
7839 20
7844 20
7876 20
7900 20
7902 20
7934 20
7369 30
7499 30
7521 30
7566 30
7654 30
7698 30
7782 30
7788 30
7839 30
7844 30
7876 30
7900 30
7902 30
7934 30
7369 40
7499 40
7521 40
7566 40
7654 40
7698 40
7782 40
7788 40
7839 40
7844 40
7876 40
7900 40
7902 40
7934 40
56 rows selected.
SQL>
SQL>
SQL> drop table dept;
Table dropped.
SQL> drop table emp;
Table dropped.
SQL>
SQL>
SQL>
Use a Cartesian product/virtual table like this:
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> -- The Use of Aggregate Functions in SQL
SQL>
SQL> -- Use a Cartesian product/virtual table like this:
SQL>
SQL>
SQL> SELECT e.empno, e.ename, e.orig_salary,
2 x.aos "Avg. salary"
3 FROM employee e,
4 (SELECT AVG(orig_salary) aos FROM employee) x
5 ORDER BY ename;
EMPNO ENAME ORIG_SALARY Avg. salary
---------- ---------- ----------- -----------
122 Alison 45000 42000
104 Celia 53000 42000
117 David 78000 42000
123 James 23000 42000
108 Jode 21000 42000
116 Linda 43000 42000
105 Robert 31000 42000
7 rows selected.
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
2 /
Table dropped.
SQL>
SQL>
SQL>
Using AVG in an analytical function: OVER()
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>
SQL> -- Using AVG in an analytical function: OVER()
SQL>
SQL>
SQL> SELECT empno, ename, orig_salary,
2 AVG(orig_salary) OVER() "Avg. salary"
3 FROM employee
4 ORDER BY ename;
EMPNO ENAME ORIG_SALARY Avg. salary
---------- ---------- ----------- -----------
122 Alison 45000 42000
104 Celia 53000 42000
117 David 78000 42000
123 James 23000 42000
108 Jode 21000 42000
116 Linda 43000 42000
105 Robert 31000 42000
7 rows selected.
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
2 /
Table dropped.
SQL>
SQL>