> For the complete documentation index, see [llms.txt](https://www.ducksql.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.ducksql.com/sql/undefined.md).

# 함수 사용하기

다양한 데이터 타입에 따른 함수 및 오퍼레이터를  제공합니다. 예를들어 숫자형의 경우 사칙연산, 텍스트형의 경우 문자열 길이 구하기등 동작을 할수 있습니다.

## 데이터 Type

대표적으로 많이 사용되는 데이터 형식은 아래와 같습니다.

* **INT, BIGINT** : 정수
* **Float, Double** : 소수점을 포함하는 숫자
* **TEXT, VARCHAR** : 텍스트
* **Timestamp** : 날짜 및 시간
* **Boolean** : 참 또는 거짓

{% hint style="info" %}
일반적인 경우 Type을 명시하지 않아도 동작하지만, Type이 필요한 경우 value**::int** 와 같이 Type을 명시할 수 있습니다.
{% endhint %}

## 숫자관련 함수

* 사칙 연산 : +, -, /, %
* ceil, floor, round 

## 텍스트 함수

* || 
* left, right
* trim
* length
* lower, upper
* substr

## 날짜 함수

* \+ interval 
* date\_trunc
* date\_diff


---

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