COUNT_DISTINCT

The COUNT_DISTINCT function counts the number of unique items in a field.

Syntax

COUNT_DISTINCT(value)

Parameters:

  • value - a field or expression that contains the items to be counted.

How the COUNT_DISTINCT function works

The COUNT_DISTINCT function takes 1 parameter, which can be the name of a metric, dimension, or expression of any type. COUNT_DISTINCT returns the total number of unique items in that field or expression.

To count all items, including duplicates, use COUNT.

There are 2 other ways to apply this function:

COUNT_DISTINCT Example

COUNT_DISTINCT(Page) - counts the number of non-unique values in the Page dimension.

Limits of COUNT_DISTINCT

You can't apply this function to a pre-aggregated field (Aggregation type of Auto), or to an expression which is the result of another aggregation function. For example, a formula such as COUNT_DISTINCT(Sessions) in a Google Analytics data source will produce an error.

To avoid possibly incurring higher query costs when using BigQuery data sources, consider using APPROX_COUNT_DISTINCT.

Was this helpful?
How can we improve it?