Float

Includes Float32, Float64, BFloat16.

Equivalent types:

  • Float32: float.
  • Float64: double.

Float types have the following aliases:

  • Float32: FLOAT, REAL, SINGLE.
  • Float64: DOUBLE, DOUBLE PRECISION.

Using floating-point numbers

  • Computations with floating-point numbers might produce a rounding error.
SELECT 1 - 0.9

┌───────minus(1, 0.9)─┐
│ 0.09999999999999998 │
└─────────────────────┘
  • The result of the calculation depends on the calculation method (the processor type and architecture of the computer system).
  • Floating-point calculations might result in numbers such as infinity (Inf) and “not-a-number” (NaN). This should be taken into account when processing the results of calculations.
  • When parsing floating-point numbers from text, the result might not be the nearest machine-representable number.

NaN and Inf

In contrast to standard SQL, the following categories of floating-point numbers are supported:

  • Inf – Infinity.

<!-- -->

SELECT 0.5 / 0

┌─divide(0.5, 0)─┐
│            inf │
└────────────────┘
  • -Inf: Negative infinity.

<!-- -->

SELECT -0.5 / 0

┌─divide(-0.5, 0)─┐
│            -inf │
└─────────────────┘
  • NaN: Not a number.

<!-- -->

SELECT 0 / 0

┌─divide(0, 0)─┐
│          nan │
└──────────────┘

See the rules for NaN sorting in the section ORDER BY clause.

BFloat16

BFloat16 is a 16-bit floating point data type with 8-bit exponent, sign, and 7-bit mantissa.

It is useful for machine learning and AI applications.

Supports conversions between Float32 and BFloat16. Most of other operations aren't supported.

Updated