# distinctCountOver


The `distinctCountOver` function calculates the distinct count of the operand partitioned by the specified attributes at a specified level. Supported levels are `PRE_FILTER` and `PRE_AGG`. The operand must be unaggregated.

## Syntax


The brackets are required. To see which arguments are optional, see the following descriptions.

```
distinctCountOver
(
  measure or dimension field 
  ,[ partition_field, ... ]  
  ,calculation level 
)
```

## Arguments


 *measure or dimension field*   
The measure or dimension that you want to do the calculation for, for example `{Sales Amt}`. Valid values are `PRE_FILTER` and `PRE_AGG`.

 *partition field*   
(Optional) One or more dimensions that you want to partition by, separated by commas.   
Each field in the list is enclosed in \$1\$1 (curly braces), if it is more than one word. The entire list is enclosed in [ ] (square brackets).

 *calculation level*  
(Optional) Specifies the calculation level to use:  
+ **`PRE_FILTER`** – Prefilter calculations are computed before the dataset filters.
+ **`PRE_AGG`** – Preaggregate calculations are computed before applying aggregations and top and bottom *N* filters to the visuals.
This value defaults to `POST_AGG_FILTER` when blank. `POST_AGG_FILTER` is not a valid level for this operation and will result in an error message. For more information, see [Using level-aware calculations in Amazon Quick](https://docs.amazonaws.cn/quicksight/latest/user/level-aware-calculations.html).

## Example


The following example gets the distinct count of `Sales` partitioned over `City` and `State` at the `PRE_AGG` level.

```
distinctCountOver
(
  Sales, 
  [City, State], PRE_AGG
)
```