Module aggregate 

Aggregate types.

Every table gets a second root field alongside its rows:

author_aggregate(where: {id: {_gt: 2}}) {
  aggregate { count, avg { salary }, max { salary } }
  nodes { id name }
}

nodes is the same list the plain root field returns, so one request can ask for a page of rows and the count of the whole set the page came from – which is the query behind every “showing 1-25 of 380” in a user interface, and the reason the two live under one field instead of two.

Which functions a column gets follows from what PostgreSQL will accept. sum and avg are offered on numeric columns only; max and min on anything that orders, which includes text and timestamps. Offering avg over a text column would put an error in the schema rather than in the client.

Enums

Returns

What an aggregate’s field is typed as.

Constants

NUMERIC_AGGREGATES

Aggregates over numbers, and the GraphQL type each returns.

ORDERED_AGGREGATES

Aggregates over anything that orders.

Functions

aggregate_fields_type_name

The name of a table’s aggregate-function type.

aggregate_type_name

The name of a table’s aggregate root type.

field_type_for

The GraphQL type name for one column under one aggregate.

function_fields_type_name

The name of the type holding one aggregate’s per-column results.

functions_for

The columns each aggregate function applies to, for one table.

is_incrementable

Whether a column can be added to.

is_numeric

Whether a column can be summed and averaged.

is_ordered

Whether a column can be ranked, which is what max and min need.

tables

Which tables get aggregate types.