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* Additional .gitignore entries * Merge a bunch of small articles about system tables into single one * Merge a bunch of small articles about formats into single one * Adapt table with formats to English docs too * Add SPb meetup link to main page * Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles * Merge MacOS.md into build_osx.md * Move Data types higher in ToC * Publish changelog on website alongside documentation * Few fixes for en/table_engines/file.md * Use smaller header sizes in changelogs * Group up table engines inside ToC * Move table engines out of top level too * Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye. * Move stuff that is part of query language into respective folder * Move table functions lower in ToC * Lost redirects.txt update * Do not rely on comments in yaml + fix few ru titles * Extract major parts of queries.md into separate articles * queries.md has been supposed to be removed * Fix weird translation * Fix a bunch of links * There is only table of contents left * "Query language" is actually part of SQL abbreviation * Change filename in README.md too * fix mistype
1.8 KiB
1.8 KiB
Float32, Float64
Types are equivalent to types of C:
Float32-floatFloat64-double
We recommend that you store data in integer form whenever possible. For example, convert fixed precision numbers to integer values, such as monetary amounts or page load times in milliseconds.
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 reading floating point numbers from rows, the result might not be the nearest machine-representable number.
NaN and Inf
In contrast to standard SQL, ClickHouse supports the following categories of floating-point numbers:
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.