# AggregateFunctionExpression (/docs/core/reference/api/interfaces/AggregateFunctionExpression)



[@kysoql/core](/docs/core/reference/api) / AggregateFunctionExpression

Typed aggregate-function expression that can be selected or compared.

## Extended by [#extended-by]

* [`AggregateFunctionBuilder`](/docs/core/reference/api/interfaces/AggregateFunctionBuilder)
* [`CountAllFunctionBuilder`](/docs/core/reference/api/interfaces/CountAllFunctionBuilder)

## Type Parameters [#type-parameters]

| Type Parameter                                                                                        | Default type                                                                     |
| ----------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- |
| `Output`                                                                                              | -                                                                                |
| `ComparisonValue`                                                                                     | `unknown`                                                                        |
| `Operator` *extends* [`ComparisonOperator`](/docs/core/reference/api/type-aliases/ComparisonOperator) | [`ComparisonOperator`](/docs/core/reference/api/type-aliases/ComparisonOperator) |

## Methods [#methods]

<a id="api-tooperationnode" />

### toOperationNode() [#tooperationnode]

```ts
toOperationNode(): AggregateFunctionNode;
```

Returns the immutable operation node represented by this expression.

#### Returns [#returns]

[`AggregateFunctionNode`](/docs/core/reference/api/type-aliases/AggregateFunctionNode)

## Properties [#properties]

| Property                                                                 | Modifier   | Type                    | Description                                                                                                        |
| ------------------------------------------------------------------------ | ---------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------ |
| <a id="api-property-expressiontype" /> `expressionType`                  | `readonly` | `Output` \| `undefined` | Type-only output marker used for fluent-query inference; implementations do not expose a meaningful runtime value. |
| <a id="api-property-comparisonvaluetype" /> `comparisonValueType?`       | `readonly` | `ComparisonValue`       | Type-only marker for values accepted when comparing this expression.                                               |
| <a id="api-property-comparisonoperatortype" /> `comparisonOperatorType?` | `readonly` | `Operator`              | Type-only marker for comparison operators supported by this expression.                                            |