Oracle PL/SQL Tutorial/Statistical Functions/AVG — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
|
(нет различий)
|
Текущая версия на 13:08, 26 мая 2010
Avg
This function returns the average or mean of a group of numbers.
The general format for this function is: AVG(expr)
<source lang="sql">
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> SELECT AVG(value) FROM myTable; AVG(VALUE)
249.99
SQL> SQL> SQL> SQL> -- clean the table SQL> drop table myTable
2 /
Table dropped. SQL> SQL></source>