# countOver


The `countOver` function calculates the count of a dimension or measure partitioned by a list of dimensions. 

## Syntax


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

```
countOver
(
  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 `sum({Sales Amt})`. Use an aggregation if the calculation level is set to `NULL` or `POST_AGG_FILTER`. Don't use an aggregation if the calculation level is set to `PRE_FILTER` or `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.
+ **`POST_AGG_FILTER`** – (Default) Table calculations are computed when the visuals display. 
This value defaults to `POST_AGG_FILTER` when blank. For more information, see [Using level-aware calculations in Quick](https://docs.amazonaws.cn/quicksight/latest/user/level-aware-calculations.html).

## Example


The following example gets the count of `Sales` partitioned over `City` and `State`. 

```
countOver
(
  Sales, 
  [City, State]
)
```

The following example gets the count of `{County}` partitioned over `City` and `State`. 

```
countOver
(
  {County}, 
  [City, State]
)
```

The following example shows the count of `Billed Amount` over `Customer Region`. The fields in the table calculation are in the field wells of the visual.

```
countOver
(
  sum({Billed Amount}),
  [{Customer Region}]
)
```

The following screenshot shows the results of the example. Because there are no other fields involved, the count is one for each region.

![\[alt text not found\]](http://docs.amazonaws.cn/en_us/quick/latest/userguide/images/countOver1.png)


If you add additional fields, the count changes. In the following screenshot, we add `Customer Segment` and `Service Line`. Each of those fields contains three unique values. With 3 segments, 3 service lines, and 3 regions, the calculated field shows 9.

![\[alt text not found\]](http://docs.amazonaws.cn/en_us/quick/latest/userguide/images/countOver2.png)


If you add the two additional fields to the partitioning fields in the calculated field, `countOver( sum({Billed Amount}), [{Customer Region}, {Customer Segment}, {Service Line}]`, then the count is again 1 for each row.

![\[alt text not found\]](http://docs.amazonaws.cn/en_us/quick/latest/userguide/images/countOver.png)