Using the LOG function : Log « Numerical Math Functions « Oracle PL/SQL Tutorial





The LOG function requires two arguments.

The first argument is the base of the log.

The second argument is the number that you want to take the log of.

In the following example, we take the log of base value 2.

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)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (2,2.11)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (3,3.44)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (5,10)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (6,3)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (8,123.45)
  2  /

1 row created.

SQL> insert into myTable(ID,  value)values (9,98.23)
  2  /

1 row created.

SQL>
SQL> select * from myTable
  2  /

        ID      VALUE
---------- ----------
         1          9
         2       2.11
         3       3.44
         5         10
         6          3
         8     123.45
         9      98.23

7 rows selected.

SQL>
SQL>
SQL> SELECT LOG(value, 2)FROM myTable
  2  /

LOG(VALUE,2)
------------
  .315464877
  .928295659
  .561038597
  .301029996
  .630929754
  .143930804
  .151100956

7 rows selected.

SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table myTable
  2  /

Table dropped.

SQL>
SQL>
SQL>
SQL>
SQL>










14.14.Log
14.14.1.Log and Exponential Functions
14.14.2.Using the LOG function
14.14.3.Get the log of 8, base 2
14.14.4.LOG(2, 4)
14.14.5.LOG(2, 5)