Oracle LOG() Function

The Oracle (PL/SQL) LOG() function returns the logarithm to the specified base of a given number. In special cases it returns the following:

If the number is less than or equal to 0, then an error is returned.
If the base is less than or equal to 0, then an error is returned.
If the base is equal to 1, then an error is returned.

Syntax

LOG(base, number)

Parameters

`base`	`Required.` Specify the number. Must be greater than 0 and not equal to 1.
`number`	`Required.` Specify the number. Must be greater than 0.

Return Value

Returns the logarithm to the specified base of a given number.

Example 1:

The example below shows the usage of LOG() function.

LOG(4, 3)
Result: .792481250360578090726869471973908254388

LOG(0.8, 0.7)
Result: 1.59841026925531125295926382550462121511

LOG(10, 0.5)
Result: -.3010299956639811952137388947244930267692

LOG(5, 25)
Result: 1.99999999999999999999999999999999999999

Example 2:

Consider a database table called Sample with the following records:

Data	x
Data 1	0.5
Data 2	1
Data 3	5
Data 4	10
Data 5	50

The statement given below can be used to calculate the base-10 logarithm of values of column x.

SELECT Sample.*, 
LOG(10, x) AS LOG_Value 
FROM Sample;

This will produce the result as shown below:

Data	x	LOG_Value
Data 1	0.5	-.3010299956639811952137388947244930267692
Data 2	1	0
Data 3	5	.6989700043360188047862611052755069732341
Data 4	10	1
Data 5	50	1.69897000433601880478626110527550697323

Example 3:

Consider a database table called Sample with the following records:

Data	x	y
Data 1	0.5	2
Data 2	2	4
Data 3	5	10
Data 4	10	10
Data 5	50	10

To calculate the logarithm of records of column y with base as records of column x, the following query can be used:

SELECT Sample.*, 
LOG(x, y) AS LOG_Value 
FROM Sample;

This will produce the result as shown below:

Data	x	y	LOG_Value
Data 1	0.5	2	-1
Data 2	2	4	1.99999999999999999999999999999999999998
Data 3	5	10	1.43067655807339305067010656876396563207
Data 4	10	10	1
Data 5	50	10	.5885919100677789540727891692371378520662

❮ Oracle Functions