Oracle PL/SQL/Analytical Functions/COVAR POP — различия между версиями
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Текущая версия на 09:55, 26 мая 2010
COVAR_POP(expr1, expr2): returns a population covariance between expr1 and expr2
SQL>
SQL>
SQL> create table TestTable (
2 x number primary key,
3 y number
4 );
Table created.
SQL> insert into TestTable values (1, 7 );
1 row created.
SQL> insert into TestTable values (2, 1 );
1 row created.
SQL> insert into TestTable values (3, 2 );
1 row created.
SQL> insert into TestTable values (4, 5 );
1 row created.
SQL> insert into TestTable values (5, 7 );
1 row created.
SQL> insert into TestTable values (6, 34 );
1 row created.
SQL> insert into TestTable values (7, 32 );
1 row created.
SQL> insert into TestTable values (8, 43 );
1 row created.
SQL> insert into TestTable values (9, 87 );
1 row created.
SQL>
SQL> select * from TestTable;
X Y
---------- ----------
1 7
2 1
3 2
4 5
5 7
6 34
7 32
8 43
9 87
9 rows selected.
SQL>
SQL> -- COVAR_POP(expr1, expr2): returns a population covariance between expr1 and expr2.
SQL>
SQL>
SQL> -- COVAR_POP(expr1, expr2)
SQL>
SQL>
SQL> SELECT COVAR_POP(y, x) FROM TestTable;
COVAR_POP(Y,X)
--------------
59.4444444
SQL>
SQL> drop table TestTable;
Table dropped.
SQL>
SQL>
SQL>