LN

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Syntax

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Scalar

ln(value)

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Arguments

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Returns

• Type: DOUBLE; FLOAT when the input is evaluated as FLOAT
• Possible values: Finite real logarithms for positive finite DOUBLE input.
• NULL behavior: DOUBLE returns NULL for NULL input or a non-finite logarithm result (including zero, negative input, NaN or positive infinity). FLOAT input preserves NULL but retains non-finite computed results.

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Properties

• Approximation bound: No fixed maximum error is guaranteed.

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Usage notes

• 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 ln(CAST(1 AS DOUBLE)) AS "value", ln(CAST(0 AS DOUBLE)) AS boundary, ln(CAST(NULL AS DOUBLE)) AS null_value;

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Values below and above one

SELECT round(ln(CAST(0.5 AS DOUBLE)), 6) AS below_one, round(ln(CAST(2 AS DOUBLE)), 6) AS above_one;

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Limitations

• DOUBLE results that are NaN or infinite become NULL. FLOAT calculations retain NaN and infinity.
• Query tools may report DOUBLE even when the result is FLOAT. The reported type does not increase the result’s precision.