Oracle PL/SQL/Numeric Math Functions/LOG — различия между версиями
Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 09:55, 26 мая 2010
Содержание
Get the log of 8, base 2
SQL> -- create demo table
SQL> create table TestTable(
2 ID VARCHAR2(4 BYTE) NOT NULL,
3 MyName VARCHAR2(10 BYTE),
4 MyDate DATE,
5 MyNumber Number(8,2)
6 )
7 /
Table created.
SQL>
SQL>
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19960711","YYYYMMDD"),12.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19970622","YYYYMMDD"),1.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19980513","YYYYMMDD"),22.1);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19990624","YYYYMMDD"),2.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("20000415","YYYYMMDD"),2.1);
1 row created.
SQL>
SQL>
SQL> select * from TestTable
2
SQL>
SQL> --Get the log of 8, base 2
SQL> SELECT LOG(2,8), LOG(2,MyNumber) FROM TestTable;
LOG(2,8) LOG(2,MYNUMBER)
---------- ---------------
3 3.59931779
3 .163498732
3 4.46597446
3 1.08406426
3 1.07038933
SQL>
SQL>
SQL>
SQL>
SQL>
SQL>
SQL> drop table TestTable;
Table dropped.
SQL>
LOG(2, 5)
SQL> select LOG(2, 5) from dual;
LOG(2,5)
----------
2.32192809
SQL>
SQL>
SQL>
LOG: The first argument is the base, and the second is the number that you want to take the log of
SQL>
SQL>
SQL> -- create demo table
SQL> create table TestTable(
2 ID VARCHAR2(4 BYTE) NOT NULL,
3 MyName VARCHAR2(10 BYTE),
4 MyDate DATE,
5 MyNumber Number(8,2)
6 )
7 /
Table created.
SQL>
SQL>
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19960711","YYYYMMDD"),12.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19970622","YYYYMMDD"),2.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19980513","YYYYMMDD"),22.1);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("19990624","YYYYMMDD"),2.12);
1 row created.
SQL> insert into TestTable (ID, MyName, MyDate, MyNumber) values("1","Alison",to_date("20000415","YYYYMMDD"),2.1);
1 row created.
SQL>
SQL>
SQL> select * from TestTable
2
SQL>
SQL> --LOG: The first argument is the base, and the second is the number that you want to take the log of
SQL>
SQL> SELECT LOG(MyNumber, 2) FROM TestTable;
LOG(MYNUMBER,2)
---------------
.277830427
.922454538
.223915297
.922454538
.934239509
SQL>
SQL>
SQL>
SQL>
SQL> drop table TestTable;
LOG(x, y):Returns the logarithm, base x, of y
SQL> --LOG(x, y):Returns the logarithm, base x, of y.
SQL>
SQL> select LOG(2, 4) from dual;
LOG(2,4)
----------
2
SQL>