ClickHouse/docs/en/query_language/functions/random_functions.md

# Functions for generating pseudo-random numbers

Non-cryptographic generators of pseudo-random numbers are used.

All the functions accept zero arguments or one argument.
If an argument is passed, it can be any type, and its value is not used for anything.
The only purpose of this argument is to prevent common subexpression elimination, so that two different instances of the same function return different columns with different random numbers.

## rand

Returns a pseudo-random UInt32 number, evenly distributed among all UInt32-type numbers.
Uses a linear congruential generator.

## rand64

Returns a pseudo-random UInt64 number, evenly distributed among all UInt64-type numbers.
Uses a linear congruential generator.

## randConstant

Returns a pseudo-random UInt32 number, The value is one for different blocks.

[Original article](https://clickhouse.yandex/docs/en/query_language/functions/random_functions/) <!--hide-->
Sources for english documentation switched to Markdown. Edit page link is fixed too for both language versions of documentation. 2017-12-28 15:13:23 +00:00			`# Functions for generating pseudo-random numbers`

Functions 2017-04-26 19:16:38 +00:00			`Non-cryptographic generators of pseudo-random numbers are used.`
Initial commit if EN docs 2017-04-03 19:49:50 +00:00
Functions 2017-04-26 19:16:38 +00:00			`All the functions accept zero arguments or one argument.`
			`If an argument is passed, it can be any type, and its value is not used for anything.`
			`The only purpose of this argument is to prevent common subexpression elimination, so that two different instances of the same function return different columns with different random numbers.`
Initial commit if EN docs 2017-04-03 19:49:50 +00:00
Sources for english documentation switched to Markdown. Edit page link is fixed too for both language versions of documentation. 2017-12-28 15:13:23 +00:00			`## rand`

Functions 2017-04-26 19:16:38 +00:00			`Returns a pseudo-random UInt32 number, evenly distributed among all UInt32-type numbers.`
			`Uses a linear congruential generator.`
Initial commit if EN docs 2017-04-03 19:49:50 +00:00
Sources for english documentation switched to Markdown. Edit page link is fixed too for both language versions of documentation. 2017-12-28 15:13:23 +00:00			`## rand64`

Functions 2017-04-26 19:16:38 +00:00			`Returns a pseudo-random UInt64 number, evenly distributed among all UInt64-type numbers.`
			`Uses a linear congruential generator.`
Sources for english documentation switched to Markdown. Edit page link is fixed too for both language versions of documentation. 2017-12-28 15:13:23 +00:00
ISSUES-3890 sync system functions to en document (#4168) * ISSUES-3890 sync system functions to en document * ISSUES-3890 fix review * ISSUES-3890 add parseDateTimeBestEffort docs * ISSUES-3890 fix review * ISSUES-3890 better sql example 2019-01-30 10:39:46 +00:00			`## randConstant`

			`Returns a pseudo-random UInt32 number, The value is one for different blocks.`
WIP on docs/website (#3383) * CLICKHOUSE-4063: less manual html @ index.md * CLICKHOUSE-4063: recommend markdown="1" in README.md * CLICKHOUSE-4003: manually purge custom.css for now * CLICKHOUSE-4064: expand <details> before any print (including to pdf) * CLICKHOUSE-3927: rearrange interfaces/formats.md a bit * CLICKHOUSE-3306: add few http headers * Remove copy-paste introduced in #3392 * Hopefully better chinese fonts #3392 * get rid of tabs @ custom.css * Apply comments and patch from #3384 * Add jdbc.md to ToC and some translation, though it still looks badly incomplete * minor punctuation * Add some backlinks to official website from mirrors that just blindly take markdown sources * Do not make fonts extra light * find . -name '.md' -type f \| xargs -I{} perl -pi -e 's//g' {} find . -name '.md' -type f \| xargs -I{} perl -pi -e 's/ sql/g' {} Remove outdated stuff from roadmap.md * Not so light font on front page too * Refactor Chinese formats.md to match recent changes in other languages 2018-10-16 10:47:17 +00:00
			`[Original article](https://clickhouse.yandex/docs/en/query_language/functions/random_functions/) <!--hide-->`