# Aggregator Functions

Aggregators are functions that group values of multiple rows into a single summary value. They are equivalent to aggregation functions that SQL supports (SUM, COUNT, AVG, MAX, MIN,...).

## count

`count(field)`

**Description**

Counts the total number of items in a group, not including NULL values.

**Return type**

Whole Number

**Example**

count(orders.id)

## count_distinct

`count_distinct(field)`

**Description**

Counts the total number of distinct items in a group, not including NULL values.

**Return type**

Whole Number

**Example**

count_distinct(orders.id)

## average

`average(field) `

**Description**

Averages the values of items in a group, not including NULL values.

**Return type**

Vary

**Example**

average(orders.id)

## min

`min(field) `

**Description**

Computes the item in the group with the smallest numeric value.

**Return type**

Vary

**Example**

min(order_item.quantity)

## max

`max(field) `

**Description**

Computes the item in the group with the largest numeric value.

**Return type**

Vary

**Example**

max(order_item.quantity)

## sum

`sum(field) `

**Description**

Sums the total number of items in a group, not including NULL values.

**Return type**

Number

**Example**

sum(order_item.quantity)

## median

`median(field) `

**Description**

Computes the median of an expression, which is the value that the values in the expression are below 50% of the time.

**Return type**

Number

**Example**

median(order_item.quantity)

## stdev

`stdev(field) `

**Description**

Returns the standard deviation (sample) of the column created by expression unless expression defines a column of lists, in which case returns the standard deviation (sample) of each list. .

**Return type**

Number

## stdevp

`stdevp(field) `

**Description**

Returns the standard deviation (population) of the column created by expression unless expression defines a column of lists, in which case returns the standard deviation (population) of each list.

**Return type**

Number

## var

`var(field) `

**Description**

Returns the variance (sample) of the column created by expression unless expression defines a column of lists, in which case returns the variance (sample) of each list.

**Return type**

Number

## varp

`varp(field) `

**Description**

Returns the variance (population) of the column created by expression unless expression defines a column of lists, in which case returns the variance (population) of each list.

**Return type**

Number