# Functions in Amazon Athena
<a name="functions"></a>

For changes in functions between Athena engine versions, see [Athena engine versioning](engine-versions.md). For a list of the time zones that can be used with the `AT TIME ZONE` operator, see [Use supported time zones](athena-supported-time-zones.md).

**Topics**
+ [Athena engine version 3](functions-env3.md)

# Athena engine version 3 functions
<a name="functions-env3"></a>

Functions in Athena engine version 3 are based on Trino. For information about Trino functions, operators, and expressions, see [Functions and operators](https://trino.io/docs/current/functions.html) and the following subsections from the Trino documentation.
+  [Aggregate](https://trino.io/docs/current/functions/aggregate.html) 
+  [Array](https://trino.io/docs/current/functions/array.html) 
+  [Binary](https://trino.io/docs/current/functions/binary.html) 
+  [Bitwise](https://trino.io/docs/current/functions/bitwise.html) 
+  [Color](https://trino.io/docs/current/functions/color.html) 
+  [Comparison](https://trino.io/docs/current/functions/comparison.html) 
+  [Conditional](https://trino.io/docs/current/functions/conditional.html) 
+  [Conversion](https://trino.io/docs/current/functions/conversion.html) 
+  [Date and time](https://trino.io/docs/current/functions/datetime.html) 
+  [Decimal](https://trino.io/docs/current/functions/decimal.html) 
+  [Geospatial](https://trino.io/docs/current/functions/geospatial.html) 
+  [HyperLogLog](https://trino.io/docs/current/functions/hyperloglog.html) 
+  [IP Address](https://trino.io/docs/current/functions/ipaddress.html) 
+  [JSON](https://trino.io/docs/current/functions/json.html) 
+  [Lambda](https://trino.io/docs/current/functions/lambda.html) 
+  [Logical](https://trino.io/docs/current/functions/logical.html) 
+  [Machine learning](https://trino.io/docs/current/functions/ml.html) 
+  [Map](https://trino.io/docs/current/functions/map.html) 
+  [Math](https://trino.io/docs/current/functions/math.html) 
+  [Quantile digest](https://trino.io/docs/current/functions/qdigest.html) 
+  [Regular expression](https://trino.io/docs/current/functions/regexp.html) 
+  [Session](https://trino.io/docs/current/functions/session.html) 
+  [Set Digest](https://trino.io/docs/current/functions/setdigest.html) 
+  [String](https://trino.io/docs/current/functions/string.html) 
+  [Table](https://trino.io/docs/current/functions/table.html) 
+  [Teradata](https://trino.io/docs/current/functions/teradata.html) 
+  [T-Digest](https://trino.io/docs/current/functions/tdigest.html) 
+  [URL](https://trino.io/docs/current/functions/url.html) 
+  [UUID](https://trino.io/docs/current/functions/uuid.html) 
+  [Window](https://trino.io/docs/current/functions/window.html) 

## invoker\$1principal() function
<a name="functions-env3-invoker-principal"></a>

The `invoker_principal` function is unique to Athena engine version 3 and is not found in Trino.

Returns a `VARCHAR` that contains the ARN of the principal (IAM role or Identity Center identity) that ran the query calling the function. For example, if the query invoker uses the permissions of an IAM role to run the query, the function returns the ARN of the IAM role. The role that runs the query must allow the `LakeFormation:GetDataLakePrincipal` action. 

### Usage
<a name="functions-invoker-principal-usage"></a>

```
SELECT invoker_principal()
```

The following table shows an example result.


****  

| \$1 | \$1col0 | 
| --- | --- | 
| 1 | arn:aws:iam::111122223333:role/Admin |