opensearch-docs-cn/_search-plugins/sql/functions.md

---
layout: default
title: Functions
parent: SQL and PPL
nav_order: 10
---

# Functions

You must enable fielddata in the document mapping for most string functions to work properly.

The specification shows the return type of the function with a generic type `T` as the argument.
For example, `abs(number T) -> T` means that the function `abs` accepts a numerical argument of type `T`, which could be any subtype of the `number` type, and it returns the actual type of `T` as the return type.

The SQL plugin supports the following common functions shared across the SQL and PPL languages.

## Mathematical

Function | Specification | Example
:--- | :--- | :---
abs | `abs(number T) -> T` | `SELECT abs(0.5) FROM my-index LIMIT 1`
add | `add(number T, number) -> T` | `SELECT add(1, 5) FROM my-index LIMIT 1`
cbrt | `cbrt(number T) -> T` | `SELECT cbrt(0.5) FROM my-index LIMIT 1`
ceil | `ceil(number T) -> T` | `SELECT ceil(0.5) FROM my-index LIMIT 1`
conv | `conv(string T, int a, int b) -> T` | `SELECT CONV('12', 10, 16), CONV('2C', 16, 10), CONV(12, 10, 2), CONV(1111, 2, 10) FROM my-index LIMIT 1`
crc32 | `crc32(string T) -> T` | `SELECT crc32('MySQL') FROM my-index LIMIT 1`
divide | `divide(number T, number) -> T` | `SELECT divide(1, 0.5) FROM my-index LIMIT 1`
e | `e() -> double` | `SELECT e() FROM my-index LIMIT 1`
exp | `exp(number T) -> T` | `SELECT exp(0.5) FROM my-index LIMIT 1`
expm1 | `expm1(number T) -> T` | `SELECT expm1(0.5) FROM my-index LIMIT 1`
floor | `floor(number T) -> T` | `SELECT floor(0.5) AS Rounded_Down FROM my-index LIMIT 1`
ln | `ln(number T) -> double` | `SELECT ln(10) FROM my-index LIMIT 1`
log | `log(number T) -> double` or `log(number T, number) -> double` | `SELECT log(10) FROM my-index LIMIT 1`
log2 | `log2(number T) -> double` | `SELECT log2(10) FROM my-index LIMIT 1`
log10 | `log10(number T) -> double` | `SELECT log10(10) FROM my-index LIMIT 1`
mod | `mod(number T, number) -> T` | `SELECT modulus(2, 3) FROM my-index LIMIT 1`
multiply | `multiply(number T, number) -> number` | `SELECT multiply(2, 3) FROM my-index LIMIT 1`
pi | `pi() -> double` | `SELECT pi() FROM my-index LIMIT 1`
pow | `pow(number T) -> T` or `pow(number T, number) -> T` | `SELECT pow(2, 3) FROM my-index LIMIT 1`
power | `power(number T) -> T` or `power(number T, number) -> T` | `SELECT power(2, 3) FROM my-index LIMIT 1`
rand | `rand() -> number` or `rand(number T) -> T` | `SELECT rand(0.5) FROM my-index LIMIT 1`
rint | `rint(number T) -> T` | `SELECT rint(1.5) FROM my-index LIMIT 1`
round | `round(number T) -> T` | `SELECT round(1.5) FROM my-index LIMIT 1`
sign | `sign(number T) -> T` | `SELECT sign(1.5) FROM my-index LIMIT 1`
signum | `signum(number T) -> T` | `SELECT signum(0.5) FROM my-index LIMIT 1`
sqrt | `sqrt(number T) -> T` | `SELECT sqrt(0.5) FROM my-index LIMIT 1`
strcmp | `strcmp(string T, string T) -> T` | `SELECT strcmp('hello', 'hello') FROM my-index LIMIT 1`
subtract | `subtract(number T, number) -> T` | `SELECT subtract(3, 2) FROM my-index LIMIT 1`
truncate | `truncate(number T, number T) -> T` | `SELECT truncate(56.78, 1) FROM my-index LIMIT 1`
/ | `number [op] number -> number` | `SELECT 1 / 100 FROM my-index LIMIT 1`
% | `number [op] number -> number` | `SELECT 1 % 100 FROM my-index LIMIT 1`

## Trigonometric

Function | Specification | Example
:--- | :--- | :---
acos | `acos(number T) -> double` | `SELECT acos(0.5) FROM my-index LIMIT 1`
asin | `asin(number T) -> double` | `SELECT asin(0.5) FROM my-index LIMIT 1`
atan | `atan(number T) -> double` | `SELECT atan(0.5) FROM my-index LIMIT 1`
atan2 | `atan2(number T, number) -> double` | `SELECT atan2(1, 0.5) FROM my-index LIMIT 1`
cos | `cos(number T) -> double` | `SELECT cos(0.5) FROM my-index LIMIT 1`
cosh | `cosh(number T) -> double` | `SELECT cosh(0.5) FROM my-index LIMIT 1`
cot | `cot(number T) -> double` | `SELECT cot(0.5) FROM my-index LIMIT 1`
degrees | `degrees(number T) -> double` | `SELECT degrees(0.5) FROM my-index LIMIT 1`
radians | `radians(number T) -> double` | `SELECT radians(0.5) FROM my-index LIMIT 1`
sin | `sin(number T) -> double` | `SELECT sin(0.5) FROM my-index LIMIT 1`
sinh | `sinh(number T) -> double` | `SELECT sinh(0.5) FROM my-index LIMIT 1`
tan | `tan(number T) -> double` | `SELECT tan(0.5) FROM my-index LIMIT 1`

## Date and time

Function | Specification | Example
:--- | :--- | :---
adddate | `adddate(date, INTERVAL expr unit) -> date` | `SELECT adddate(date('2020-08-26'), INTERVAL 1 hour) FROM my-index LIMIT 1`
curdate | `curdate() -> date` | `SELECT curdate() FROM my-index LIMIT 1`
date | `date(date) -> date` | `SELECT date() FROM my-index LIMIT 1`
date_format | `date_format(date, string) -> string` or `date_format(date, string, string) -> string` | `SELECT date_format(date, 'Y') FROM my-index LIMIT 1`
date_sub | `date_sub(date, INTERVAL expr unit) -> date` | `SELECT date_sub(date('2008-01-02'), INTERVAL 31 day) FROM my-index LIMIT 1`
dayofmonth | `dayofmonth(date) -> integer` | `SELECT dayofmonth(date) FROM my-index LIMIT 1`
dayname | `dayname(date) -> string` | `SELECT dayname(date('2020-08-26')) FROM my-index LIMIT 1`
dayofyear | `dayofyear(date) -> integer` | `SELECT dayofyear(date('2020-08-26')) FROM my-index LIMIT 1`
dayofweek | `dayofweek(date) -> integer` | `SELECT dayofweek(date('2020-08-26')) FROM my-index LIMIT 1`
from_days | `from_days(N) -> integer` | `SELECT from_days(733687) FROM my-index LIMIT 1`
hour | `hour(time) -> integer` | `SELECT hour((time '01:02:03')) FROM my-index LIMIT 1`
maketime | `maketime(integer, integer, integer) -> date` | `SELECT maketime(1, 2, 3) FROM my-index LIMIT 1`
microsecond | `microsecond(expr) -> integer` | `SELECT microsecond((time '01:02:03.123456')) FROM my-index LIMIT 1`
minute | `minute(expr) -> integer` | `SELECT minute((time '01:02:03')) FROM my-index LIMIT 1`
month | `month(date) -> integer` | `SELECT month(date) FROM my-index`
monthname | `monthname(date) -> string` | `SELECT monthname(date) FROM my-index`
now | `now() -> date` | `SELECT now() FROM my-index LIMIT 1`
quarter | `quarter(date) -> integer` | `SELECT quarter(date('2020-08-26')) FROM my-index LIMIT 1`
second | `second(time) -> integer` | `SELECT second((time '01:02:03')) FROM my-index LIMIT 1`
subdate | `subdate(date, INTERVAL expr unit) -> date, datetime` | `SELECT subdate(date('2008-01-02'), INTERVAL 31 day) FROM my-index LIMIT 1`
time | `time(expr) -> time` | `SELECT time('13:49:00') FROM my-index LIMIT 1`
time_to_sec | `time_to_sec(time) -> long` | `SELECT time_to_sec(time '22:23:00') FROM my-index LIMIT 1`
timestamp | `timestamp(date) -> date` | `SELECT timestamp(date) FROM my-index LIMIT 1`
to_days | `to_days(date) -> long` | `SELECT to_days(date '2008-10-07') FROM my-index LIMIT 1`
week | `week(date[mode])  -> integer` | `SELECT week(date('2008-02-20')) FROM my-index LIMIT 1`
year | `year(date) -> integer` | `SELECT year(date) FROM my-index LIMIT 1`

## String

Function | Specification | Example
:--- | :--- | :---
ascii | `ascii(string T) -> integer` | `SELECT ascii(name.keyword) FROM my-index LIMIT 1`
concat | `concat(str1, str2) -> string` | `SELECT concat('hello', 'world') FROM my-index LIMIT 1`
concat_ws | `concat_ws(separator, string, string…) -> string` | `SELECT concat_ws("-", "Tutorial", "is", "fun!") FROM my-index LIMIT 1`
left | `left(string T, integer) -> T` | `SELECT left('hello', 2) FROM my-index LIMIT 1`
length | `length(string) -> integer` | `SELECT length('hello') FROM my-index LIMIT 1`
locate | `locate(string, string, integer) -> integer` or `locate(string, string) -> INTEGER` | `SELECT locate('o', 'hello') FROM my-index LIMIT 1`, `SELECT locate('l', 'hello', 3) FROM my-index LIMIT 1`
replace | `replace(string T, string, string) -> T` | `SELECT replace('hello', 'l', 'x') FROM my-index LIMIT 1`
right | `right(string T, integer) -> T` | `SELECT right('hello', 1) FROM my-index LIMIT 1`
rtrim | `rtrim(string T) -> T` | `SELECT rtrim(name.keyword) FROM my-index LIMIT 1`
substring | `substring(string T, integer, integer) -> T` | `SELECT substring(name.keyword, 2,5) FROM my-index LIMIT 1`
trim | `trim(string T) -> T` | `SELECT trim('   hello') FROM my-index LIMIT 1`
upper | `upper(string T) -> T` | `SELECT upper('helloworld') FROM my-index LIMIT 1`

## Aggregate

Function | Specification | Example
:--- | :--- | :---
avg | `avg(number T) -> T` | `SELECT avg(2, 3) FROM my-index LIMIT 1`
count | `count(number T) -> T` | `SELECT count(date) FROM my-index LIMIT 1`
min | `min(number T, number) -> T` | `SELECT min(2, 3) FROM my-index LIMIT 1`
show | `show(string T) -> T` | `SHOW TABLES LIKE my-index`

## Advanced

Function | Specification | Example
:--- | :--- | :---
if | `if(boolean, es_type, es_type) -> es_type` | `SELECT if(false, 0, 1) FROM my-index LIMIT 1`, `SELECT if(true, 0, 1) FROM my-index LIMIT 1`
ifnull | `ifnull(es_type, es_type) -> es_type` | `SELECT ifnull('hello', 1) FROM my-index LIMIT 1`, `SELECT ifnull(null, 1) FROM my-index LIMIT 1`
isnull | `isnull(es_type) -> integer` | `SELECT isnull(null) FROM my-index LIMIT 1`, `SELECT isnull(1) FROM my-index LIMIT 1`

## Relevance-based search (full-text search)

These functions are only available in the `WHERE` clause. For their descriptions and usage examples in SQL and PPL, see [Full-text search]({{site.url}}{{site.baseurl}}/search-plugins/sql/full-text/).