---
title: Ordering
---

> [!WARNING]
> The legacy ordering behavior described in this document is provided for backwards compatibility.
> You should prefer the new [Ordering](ordering.md) system instead.

# Order (Legacy)

The legacy ordering system created with `@strawberry_django.order` allows sorting by multiple fields only by specifying the object keys in the order input
in the desired order. This is not always feasible and contradicts the way objects are supposed to be used.

```python title="types.py"
@strawberry_django.order(models.Color)
class ColorOrder:
    name: auto


@strawberry_django.order(models.Fruit)
class FruitOrder:
    name: auto
    color: ColorOrder | None
```

> [!TIP]
> In most cases order fields should have `Optional` annotations and default value `strawberry.UNSET`.
> Above `auto` annotation is wrapped in `Optional` automatically.
> `UNSET` is automatically used for fields without `field` or with `strawberry_django.order_field`.

The code above generates the following schema:

```graphql title="schema.graphql"
enum Ordering {
  ASC
  ASC_NULLS_FIRST
  ASC_NULLS_LAST
  DESC
  DESC_NULLS_FIRST
  DESC_NULLS_LAST
}

input ColorOrder {
  name: Ordering
}

input FruitOrder {
  name: Ordering
  color: ColorOrder
}
```

## Custom order methods

You can define custom order method by defining your own resolver.

```python title="types.py"
@strawberry_django.order(models.Fruit)
class FruitOrder:
    name: auto

    @strawberry_django.order_field
    def discovered_by(self, value: bool, prefix: str) -> list[str]:
        if not value:
            return []
        return [f"{prefix}discover_by__name", f"{prefix}name"]

    @strawberry_django.order_field
    def order_number(
        self,
        info: Info,
        queryset: QuerySet,
        value: strawberry_django.Ordering,  # `auto` can be used instead
        prefix: str,
        sequence: dict[str, strawberry_django.Ordering] | None,
    ) -> tuple[QuerySet, list[str]] | list[str]:
        queryset = queryset.alias(_ordered_num=Count(f"{prefix}orders__id"))
        ordering = value.resolve(f"{prefix}_ordered_num")
        return queryset, [ordering]
```

> [!WARNING]
> Do not use `queryset.order_by()` directly. Due to `order_by` not being chainable
> operation, changes applied this way would be overriden later.

> [!TIP]
> The `strawberry_django.Ordering` type has convenient method `resolve` that can be used to
> convert field's name to appropriate `F` object with correctly applied `asc()`, `desc()` method
> with `nulls_first` and `nulls_last` arguments.

The code above generates the following schema:

```graphql title="schema.graphql"
enum Ordering {
  ASC
  ASC_NULLS_FIRST
  ASC_NULLS_LAST
  DESC
  DESC_NULLS_FIRST
  DESC_NULLS_LAST
}

input FruitOrder {
  name: Ordering
  discoveredBy: bool
  orderNumber: Ordering
}
```

#### Resolver arguments

- `prefix` - represents the current path or position
  - **Required**
  - Important for nested ordering
  - In code bellow custom order `name` ends up ordering `Fruit` instead of `Color` without applying `prefix`

```python title="Why prefix?"
@strawberry_django.order(models.Fruit)
class FruitOrder:
    name: auto
    color: ColorOrder | None


@strawberry_django.order(models.Color)
class ColorOrder:
    @strawberry_django.order_field
    def name(self, value: bool, prefix: str):
        # prefix is "fruit_set__" if unused root object is ordered instead
        if value:
            return ["name"]
        return []
```

```graphql
{
  fruits( order: {color: name: ASC} ) { ... }
}
```

- `value` - represents graphql field type
  - **Required**, but forbidden for default `order` method
  - _must_ be annotated
  - used instead of field's return type
  - Using `auto` is the same as `strawberry_django.Ordering`.
- `queryset` - can be used for more complex ordering
  - Optional, but **Required** for default `order` method
  - usually used to `annotate` `QuerySet`
- `sequence` - used to order values on the same level
  - elements in graphql object are not quaranteed to keep their order as defined by user thus
    this argument should be used in those cases
    [GraphQL Spec](https://spec.graphql.org/October2021/#sec-Language.Arguments)
  - usually for custom order field methods does not have to be used
  - for advanced usage, look at `strawberry_django.process_order` function

#### Resolver return

For custom field methods two return values are supported

- iterable of values acceptable by `QuerySet.order_by` -> `Collection[F | str]`
- tuple with `QuerySet` and iterable of values acceptable by `QuerySet.order_by` -> `tuple[QuerySet, Collection[F | str]]`

For default `order` method only second variant is supported.

### What about nulls?

By default `null` values are ignored. This can be toggled as such `@strawberry_django.order_field(order_none=True)`

## Overriding the default `order` method

Works similar to field order method, but:

- is responsible for resolution of ordering for entire object
- _must_ be named `order`
- argument `queryset` is **Required**
- argument `value` is **Forbidden**
- should probably use `sequence`

```python title="types.py"
@strawberry_django.order(models.Fruit)
class FruitOrder:
    name: auto

    @strawberry_django.order_field
    def ordered(
        self,
        info: Info,
        queryset: QuerySet,
        value: strawberry_django.Ordering,
        prefix: str,
    ) -> tuple[QuerySet, list[str]] | list[str]:
        queryset = queryset.alias(_ordered_num=Count(f"{prefix}orders__id"))
        return queryset, [value.resolve(f"{prefix}_ordered_num")]

    @strawberry_django.order_field
    def order(
        self,
        info: Info,
        queryset: QuerySet,
        prefix: str,
        sequence: dict[str, strawberry_django.Ordering] | None,
    ) -> tuple[QuerySet, list[str]]:
        queryset = queryset.filter(
            ...  # Do some query modification
        )

        return strawberry_django.process_order(
            self,
            info=info,
            queryset=queryset,
            sequence=sequence,
            prefix=prefix,
            skip_object_order_method=True,
        )
```

> [!TIP]
> As seen above `strawberry_django.process_order` function is exposed and can be
> reused in custom methods.
> For order method `order` `skip_object_order_method` was used to avoid endless recursion.

## Adding orderings to types

All fields and mutations inherit orderings from the underlying type by default.
So, if you have a field like this:

```python title="types.py"
@strawberry_django.type(models.Fruit, order=FruitOrder)
class Fruit: ...
```

The `fruits` field will inherit the `order` of the type same same way as
if it was passed to the field.

## Adding orderings directly into a field

Orderings added into a field override the default order of this type.

```python title="schema.py"
@strawberry.type
class Query:
    fruit: Fruit = strawberry_django.field(order=FruitOrder)
```
