Documentdb Sql 简明教程

DocumentDB SQL - Built-in Function

DocumentDB 支持各种内置函数，用于可以在查询内使用的常见操作。有一系列函数可用于执行数学计算，还有在使用各种模式时非常有用的类型检查函数。这些函数可以测试某个属性是否存在，以及如果存在，它是否为数字、字符串、布尔值或对象。

DocumentDB supports a host of built-in functions for common operations that can be used inside queries. There are a bunch of functions for performing mathematical calculations, and also type checking functions that are extremely useful while working with varying schemas. These functions can test if a certain property exists and if it does whether it’s a number or a string, Boolean or object.

我们还获得了用于解析和操作字符串的这些便捷函数，以及用于处理数组的几个函数，这些函数允许您执行诸如连接数组和测试数组是否包含特定元素之类的操作。

We also get these handy functions for parsing and manipulating strings, as well as several functions for working with arrays allowing you to do things like concatenate arrays and test to see if an array contains a particular element.

以下是内置函数不同类型 -

Following are the different types of built-in functions −

S.No.	Built-in Functions & Description
1	Mathematical FunctionsThe mathematical functions perform a calculation, usually based on input values that are provided as arguments, and return a numeric value.
2	Type Checking FunctionsThe type checking functions allow you to check the type of an expression within SQL queries.
3	String FunctionsThe string functions perform an operation on a string input value and return a string, numeric or Boolean value.
4	Array FunctionsThe array functions perform an operation on an array input value and return in the form of numeric, Boolean or array value.
5	Spatial FunctionsDocumentDB also supports the Open Geospatial Consortium (OGC) built-in functions for geospatial querying.