====== Count Distinct (Expression Function) ======

===== Purpose =====
The **Count Distinct** function (COUNT_DISTINCT) is used to count the number of unique values returned by a certain query. It does not add the values together to achieve that use the [[Expression Function - Sum|Sum]] function.  If the total number of values is needed regardless of duplicates then the [[Expression Function - Count|Count]] function should be used.

{{::count_distinct_initial.png?direct&600|}}

===== Parameters =====
The **Count Distinct** function has one parameters:

==== Field Value ====

Allowed Inputs: [[Field|field]] values

The parameter of the **Count Distinct** function are the field values to be counted.  The input is a query built using the [[Query Builder]] to find [[Field|field]] values on one or many [[record|record(s)]] in a [[Table|table]].

===== Output =====

The output of the **Count Distinct** function is a number representing a count of all the unique values found.
===== Example =====

If an Invoice record has 4 related Line Item records, and those records have values of -6, 8, 8, and 24 in the Quantity field, COUNT(${Line Item ~> Quantity}) would result in 3.