REVERSE - MaxCompute - Alibaba Cloud Documentation Center

Returns a string or an array in reverse order.

Syntax

string|array reverse(string|array <value>)

Parameters

value: required. A value of the STRING or ARRAY data type. If the input value is of the BIGINT, DOUBLE, DECIMAL, or DATETIME type, the input value is implicitly converted into a value of the STRING type before calculation.

Return value

A value of the STRING or ARRAY type is returned. The return value varies based on the following rules:

If the input value specified by value cannot be converted into a value of the STRING or ARRAY type, an error is returned.
If the value parameter is null, null is returned.

Examples

Example 1: Return a string whose characters are in reverse order of the string I love aliyun very much. Sample statement:
```
-- The return value is hcum yrev nuyila evol I. 
select reverse('I love aliyun very much');
```
Example 2: An input parameter is set to null. Sample statement:
```
-- The return value is null. 
select reverse(null);
```
Example 3: Return an array whose elements are in reverse order of the array [2, 1, 4, 3]. Sample statement:
```
-- The return value is [3, 4, 1, 2].
SELECT reverse(array(2, 1, 4, 3));
```

Related functions

REVERSE is a string function. For more information about functions related to string searches and conversion, see String functions.