LOG

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Syntax

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Scalar

log(base, value)

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Arguments

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Returns

• Type: DOUBLE for DECIMAL or integer input; FLOAT when the input is evaluated as FLOAT
• Possible values: A floating-point logarithm; invalid mathematical domains produce NaN or infinity.
• NULL behavior: Returns NULL when an argument is NULL.

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Properties

• Approximation bound: No fixed maximum error is guaranteed.

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Usage notes

• Decimal perfect powers at scale zero may use exact integer logarithm detection before falling back to floating point.
• INTEGER and INT mean the same type; STRING means VARCHAR text. NULL can be used with a supported type. Cast NULL explicitly when its type would otherwise be unclear.
• Exact result: Floating-point computation can round the mathematical result.

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Examples

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Value and NULL input

SELECT log(CAST(2 AS DOUBLE), CAST(8 AS DOUBLE)) AS "value", log(CAST(NULL AS DOUBLE), CAST(8 AS DOUBLE)) AS null_value;

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Change the base

SELECT log(CAST(10 AS DOUBLE), CAST(100 AS DOUBLE)) AS base_10, log(CAST(2 AS DOUBLE), CAST(0.5 AS DOUBLE)) AS base_2;

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Limitations

• Supply two numeric arguments. The one-argument base-10 form is not supported. An input evaluated as FLOAT returns FLOAT even when query tools report DOUBLE.