# Regex SerDe
<a name="regex-serde"></a>

The Regex SerDe uses a regular expression (regex) to deserialize data by extracting regex groups into table columns. 

If a row in the data does not match the regex, then all columns in the row are returned as `NULL`. If a row matches the regex but has fewer groups than expected, the missing groups are `NULL`. If a row in the data matches the regex but has more columns than groups in the regex, the additional columns are ignored. 

For more information, see [Class RegexSerDe](https://svn.apache.org/repos/infra/websites/production/hive/content/javadocs/r1.2.2/api/org/apache/hadoop/hive/serde2/RegexSerDe.html) in the Apache Hive documentation.

## Serialization library name
<a name="regex-serde-library-name"></a>

The serialization library name for the Regex SerDe is `org.apache.hadoop.hive.serde2.RegexSerDe`. For source code information, see [Class RegexSerDe](https://svn.apache.org/repos/infra/websites/production/hive/content/javadocs/r1.2.2/api/org/apache/hadoop/hive/serde2/RegexSerDe.html) In the Apache documentation. 

## Example
<a name="regex-serde-examples"></a>

The following example creates a table from CloudFront logs using the RegExSerDe. Replace *myregion* in `s3://athena-examples-myregion/cloudfront/plaintext/` with the region identifier where you run Athena (for example, `s3://athena-examples-us-west-1/cloudfront/plaintext/`).

```
CREATE EXTERNAL TABLE IF NOT EXISTS cloudfront_logs (
  `Date` DATE,
  Time STRING,
  Location STRING,
  Bytes INT,
  RequestIP STRING,
  Method STRING,
  Host STRING,
  Uri STRING,
  Status INT,
  Referrer STRING,
  os STRING,
  Browser STRING,
  BrowserVersion STRING
 ) 
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.RegexSerDe'
 WITH SERDEPROPERTIES (
 "input.regex" = "^(?!#)([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+([^ ]+)\\s+[^\(]+[\(]([^\;]+).*\%20([^\/]+)[\/](.*)$"
 ) 
LOCATION 's3://athena-examples-myregion/cloudfront/plaintext/';
```