Oracle PL/SQL Tutorial/Linear Regression Functions/REGR AVGX — различия между версиями
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Текущая версия на 10:06, 26 мая 2010
For average value of independent (x) variables: REGR_AVGX(expr1, expr2)
SQL>
SQL> -- create demo table
SQL> create table myTable(
2 id NUMBER(2),
3 value NUMBER(6,2)
4 )
5 /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into myTable(ID, value)values (1,9);
1 row created.
SQL> insert into myTable(ID, value)values (2,2.11);
1 row created.
SQL> insert into myTable(ID, value)values (3,3.44);
1 row created.
SQL> insert into myTable(ID, value)values (4,-4.21);
1 row created.
SQL> insert into myTable(ID, value)values (5,10);
1 row created.
SQL> insert into myTable(ID, value)values (6,3);
1 row created.
SQL> insert into myTable(ID, value)values (7,-5.88);
1 row created.
SQL> insert into myTable(ID, value)values (8,123.45);
1 row created.
SQL> insert into myTable(ID, value)values (9,98.23);
1 row created.
SQL> insert into myTable(ID, value)values (10,938.23);
1 row created.
SQL> insert into myTable(ID, value)values (11,984.23);
1 row created.
SQL> insert into myTable(ID, value)values (12,198.23);
1 row created.
SQL> insert into myTable(ID, value)values (13,928.87);
1 row created.
SQL> insert into myTable(ID, value)values (14,25.37);
1 row created.
SQL> insert into myTable(ID, value)values (15,918.3);
1 row created.
SQL> insert into myTable(ID, value)values (16,9.23);
1 row created.
SQL> insert into myTable(ID, value)values (17,8.23);
1 row created.
SQL>
SQL> select * from myTable
2 /
ID VALUE
---------- ----------
1 9
2 2.11
3 3.44
4 -4.21
5 10
6 3
7 -5.88
8 123.45
9 98.23
10 938.23
11 984.23
ID VALUE
---------- ----------
12 198.23
13 928.87
14 25.37
15 918.3
16 9.23
17 8.23
17 rows selected.
SQL>
SQL>
SQL>
SQL> SELECT REGR_AVGX(value, id) FROM myTable;
REGR_AVGX(VALUE,ID)
-------------------
9
SQL>
SQL>
SQL> -- clean the table
SQL> drop table myTable
2 /
Table dropped.
SQL>
REGR_AVGX returns the average of x after eliminating x and y pairs where either x or y is null
SQL>
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","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","James", "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 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager
08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester
8 rows selected.
SQL>
SQL>
SQL> SELECT
2 REGR_AVGY(salary, city) AS avgy
3 FROM employee
4 GROUP BY city;
AVGY
----------
6110.28
1234.56
3823.78
SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
2 /
Table dropped.
SQL>
SQL>