ClickHouse/docs/en/sql-reference/aggregate-functions/reference/uniqexact.md

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# uniqExact {#agg_function-uniqexact}

Calculates the exact number of different argument values.

``` sql
uniqExact(x[, ...])
```

Use the `uniqExact` function if you absolutely need an exact result. Otherwise use the [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq) function.

The `uniqExact` function uses more memory than `uniq`, because the size of the state has unbounded growth as the number of different values increases.

**Parameters**

The function takes a variable number of parameters. Parameters can be `Tuple`, `Array`, `Date`, `DateTime`, `String`, or numeric types.

**See Also**

-   [uniq](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniq)
-   [uniqCombined](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniqcombined)
-   [uniqHLL12](../../../sql-reference/aggregate-functions/reference/uniq.md#agg_function-uniqhll12)