LN()

All functions > MATH > LN()

Returns the natural logarithm (base e) of a number.

Signatures

Natural logarithm

Returns: Natural logarithm of the input

LN(number: T) → DOUBLE

With:

• T : Floating-point type (FLOAT, DOUBLE)

Signature notes:

• Only defined for positive numbers
• LN(1.0) = 0, LN(e) = 1
• Returns NULL if the input is NULL
• Returns negative infinity for 0, NaN for negative numbers
• Inverse of EXP: LN(EXP(x)) = x

Examples

SELECT
    f1 := LN(1.0E0), -- ln(1) is 0
    f2 := LN(2.718281828459045E0), -- ln(e) is 1
    f3 := LN(10.0E0), -- Natural log of 10
    f4 := LN(0.5E0) -- Natural log below 1 is negative
;