CockroachDB supports various inexact, floating-point number data types with up to 17 digits of decimal precision.

They are handled internally using the standard double-precision (64-bit binary-encoded) IEEE754 format.

Names and Aliases

Name Aliases
FLOAT None
REAL FLOAT4
DOUBLE PRECISION FLOAT8

Syntax

A constant value of type FLOAT can be entered as a numeric literal. For example: 1.414 or -1234.

The special IEEE754 values for positive infinity, negative infinity and NaN (Not-a-Number) cannot be entered using numeric literals directly and must be converted using an interpreted literal or an explicit conversion from a string literal instead.

The following values are recognized:

Syntax Value
inf, infinity, +inf, +infinity +∞
-inf, -infinity -∞
nan NaN (Not-a-Number)

For example:

  • FLOAT '+Inf'
  • '-Inf'::FLOAT
  • CAST('NaN' AS FLOAT)

Size

A FLOAT column supports values up to 8 bytes in width, but the total storage size is likely to be larger due to CockroachDB metadata.

Examples

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> CREATE TABLE floats (a FLOAT PRIMARY KEY, b REAL, c DOUBLE PRECISION);
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> SHOW COLUMNS FROM floats;
+-------------+------------------+-------------+----------------+-----------------------+-------------+
| column_name |    data_type     | is_nullable | column_default | generation_expression |   indices   |
+-------------+------------------+-------------+----------------+-----------------------+-------------+
| a           | FLOAT            |    false    | NULL           |                       | {"primary"} |
| b           | REAL             |    true     | NULL           |                       | {}          |
| c           | DOUBLE PRECISION |    true     | NULL           |                       | {}          |
+-------------+------------------+-------------+----------------+-----------------------+-------------+
(3 rows)
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> INSERT INTO floats VALUES (1.012345678901, 2.01234567890123456789, CAST('+Inf' AS FLOAT));
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> SELECT * FROM floats;
+----------------+--------------------+------+
|       a        |         b          |  c   |
+----------------+--------------------+------+
| 1.012345678901 | 2.0123456789012346 | +Inf |
+----------------+--------------------+------+
(1 row)
# Note that the value in "b" has been limited to 17 digits.

Supported casting and conversion

FLOAT values can be cast to any of the following data types:

Type Details
INT Truncates decimal precision and requires values to be between -2^63 and 2^63-1
DECIMAL Causes an error to be reported if the value is NaN or +/- Inf.
BOOL 0 converts to false; all other values convert to true
STRING --

See also

Data Types



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