# unnest
<a name="CWL_QuerySyntax-Unnest"></a>

 Use `unnest` to flatten a list taken as input to produce multiple records with a single record for each element in the list. Based on the number of items a field contains, this command discards the current record and generates new records. Each record includes the `unnested_field`, which represents an item. All other fields come from the original record. 

 The input for `unnest` is `LIST`, which comes from the `jsonParse` function. For more information, see [Structure types](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CWL_QuerySyntax-operations-functions.html#CWL_QuerySyntax-structure-types). Any other types, such as `MAP`, `String` and `numbers`, are treated as a list with one item in `unnest`. 

**Command structure**  
 The following example describes the format of this command. 

```
unnest field into unnested_field
```

**Example query**  
 The following example parses a JSON object string and expands a list of field events. 

```
fields jsonParse(@message) as json_message 
| unnest json_message.events into event
| display event.name
```

The log event for this example query could be a JSON string as follows:

```
{
   "events": [
        {
            "name": "exception"
        },
        {
            "name": "user action"
        }
   ]
}
```

In this case, the sample query produces two records in the query result, one with `event.name` as `exception` and another with `event.name` as **user action**

**Example query**  
 The following example flattens a list and then filters out items. 

```
fields jsonParse(@message) as js 
| unnest js.accounts into account 
| filter account.type = "internal"
```

**Example query**  
 The following example flattens a list for aggregation. 

```
fields jsonParse(trimmedData) as accounts 
| unnest accounts into account 
| stats sum(account.droppedSpans) as n by account.accountId 
| sort n desc 
| limit 10
```