## `Path`-, `Query`- und Body-Parameter vermischen

Zuerst einmal, Sie können `Path`-, `Query`- und Requestbody-Parameter-Deklarationen frei mischen und **FastAPI** wird wissen, was zu tun ist.

Und Sie können auch Body-Parameter als optional kennzeichnen, indem Sie den Defaultwert auf `None` setzen:

{* ../../docs_src/body_multiple_params/tutorial001_an_py310.py hl[18:20] *}

/// note | Hinweis

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      Contribution(s) alone or by combination of their Contribution(s)
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      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a

      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a

      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a

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`Optional[Something]` ist tatsächlich eine Abkürzung für `Union[Something, None]`, diese beiden sind äquivalent.

Das bedeutet auch, dass Sie in Python 3.10 `Something | None` verwenden können:

//// tab | Python 3.10+

```Python hl_lines="1"

In diesem Fall wird der Funktionsparameter `q` optional, und standardmäßig `None` sein.

/// check

Beachten Sie auch, dass **FastAPI** intelligent genug ist, um zu erkennen, dass `item_id` ein Pfad-Parameter ist und `q` keiner, daher muss letzteres ein Query-Parameter sein.

///

## Query-Parameter Typkonvertierung

Sie können auch `bool`-Typen deklarieren und sie werden konvertiert:

{* ../../docs_src/query_params/tutorial003_py310.py hl[7] *}