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The LOG SQL Function in MySQL and MariaDB - Logarithm to the base

LOG	Syntax:	LOG([Base], Number)
	Return value:	FLOAT
	Synonyms:	LN
	Function type:	Numeric function

Function Description

If the "Base" is not specified, the LOG() function returns the natural logarithm of "Number".

If the value of "Number" is less than or equal to 0, NULL is returned.

If the "Base" is specified, it returns the logarithm of "Number" to the "Base".

If "Base" is less than or equal to 1 or "Number" is less than or equal to 0, NULL is returned.

If "Number" or "Base" is NULL, NULL is returned.

The reverse function without "Base" is the EXP() function.

Examples without specifying the base


select log(2.4) as result;
select log(2) as result;
select log(-2) as result;

result
double(23)
0.8754687373538999

result
double(23)
0.6931471805599453

result
double(23)
NULL

Examples with specifying the base


select log(2,2) as result;
select log(4,2) as result;
select log(16,2) as result;

result
double(23)
1

result
double(23)
0.5

result
double(23)
0.25

The examples were created with the MyWAY SQL manager: Download

How to use the LOG() function in MySQL and MariaDB databases

The LOG() function in MySQL and MariaDB can be used to calculate the logarithm with different bases, including the natural logarithm (base e). The function is widely used in various mathematical and scientific calculations, such as calculating exponential growth rates or decay rates, solving equations with logarithms, or working with logarithmic scales. The LOG() function uses floating point arithmetic, so the precision of the result depends on the underlying data type.

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ASIN	ASIN(Number)
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COS	COS(Number)
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COT	COT(Number)
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DEGREES	DEGREES(Number)
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EXP	EXP(Number)
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LN	LN(Number)
	More about LN Function

LOG10	LOG10(Number)
	More about LOG10 Function

LOG2	LOG2(Number)
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MOD	MOD(Number, Divider)
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POW	POW(Number, Exponent)
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POWER	POWER(Number, Exponent)
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PI	PI()
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RADIANS	RADIANS(Number)
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RAND	RAND([Number])
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ROUND	ROUND(Number [, Decimals])
	More about ROUND Function

SIN	SIN(Number)
	More about SIN Function

SQRT	SQRT(Number)
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TAN	TAN(Number)
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TRUNCATE	TRUNCATE(Number, Decimals)
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More information about the LOG SQL function: mysql.com and mariadb.com and w3schools.com

Updated: 2023-09-24

2020-2024 Heino Cunze-Fischer