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> Reference material for ARRAY_COUNT_DISTINCT function

# ARRAY_COUNT_DISTINCT

Returns the number of distinct (unique) elements in the array. As with `COUNT` and `COUNT(DISTINCT ...)` aggregations, `NULL` is not counted as a value if it occurs.

## Syntax

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
ARRAY_COUNT_DISTINCT(<array>)
```

## Parameters

| Parameter | Description                                        | Supported input types |
| :-------- | :------------------------------------------------- | :-------------------- |
| `<array>` | The array of which to count the distinct elements. | Any `ARRAY` type      |

## Return Type

`INTEGER`

## Example

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT ARRAY_COUNT_DISTINCT([ 1, 2, 4, 5, 2, NULL, 5, 1 ]) AS res;
```

**Returns**: `4`