ClickHouse/docs/en/sql-reference/aggregate-functions/reference/sumkahan.md

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sumKahan

Calculates the sum of the numbers with Kahan compensated summation algorithm Slower than sum function. The compensation works only for Float types.

Syntax

sumKahan(x)

Arguments

• x — Input value, must be Integer, Float, or Decimal.

Returned value

• the sum of numbers, with type Integer, Float, or Decimal depends on type of input arguments

Example

Query:

SELECT sum(0.1), sumKahan(0.1) FROM numbers(10);

Result:

┌───────────sum(0.1)─┬─sumKahan(0.1)─┐
│ 0.9999999999999999 │             1 │
└────────────────────┴───────────────┘