# 请求体 - 多个参数

既然我们已经知道了如何使用 `Path` 和 `Query`，下面让我们来了解一下请求体声明的更高级用法。

## 混合使用 `Path`、`Query` 和请求体参数

首先，毫无疑问地，你可以随意地混合使用 `Path`、`Query` 和请求体参数声明，**FastAPI** 会知道该如何处理。

你还可以通过将默认值设置为 `None` 来将请求体参数声明为可选参数：

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

/// note

请注意，在这种情况下，将从请求体获取的 `item` 是可选的。因为它的默认值为 `None`。

///

## 多个请求体参数

在上面的示例中，*路径操作*将期望一个具有 `Item` 的属性的 JSON 请求体，就像：

```JSON

		t.Errorf("failed to query users count, got error: %v, count: %v", err, count)
	}

	if err := DB.Model(&User{}).Distinct("name").Where("name like ?", "distinct%").Count(&count).Error; err != nil || count != 3 {
		t.Errorf("failed to query users count, got error: %v, count %v", err, count)
	}

	dryDB := DB.Session(&gorm.Session{DryRun: true})

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(
        default=None, min_length=3, max_length=50, pattern="^fixedquery$"
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[Union[str, None], Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None, Query(min_length=3, max_length=50, regex="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        Union[str, None], Query(min_length=3, max_length=50, pattern="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: list[str] = Query(default=["foo", "bar"])):
    query_items = {"q": q}

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(default=None, title="Query string", min_length=3),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

{* ../../docs_src/body/tutorial003_py310.py hl[15:16] *}


## Request body + path + query parameters { #request-body-path-query-parameters }

You can also declare **body**, **path** and **query** parameters, all at the same time.

**FastAPI** will recognize each of them and take the data from the correct place.

from typing import Annotated

import pytest
from fastapi import Body, FastAPI, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.post("/")
async def get(
    x: Annotated[float, Query(allow_inf_nan=True)] = 0,
    y: Annotated[float, Query(allow_inf_nan=False)] = 0,
    z: Annotated[float, Query()] = 0,
    b: Annotated[float, Body(allow_inf_nan=False)] = 0,
) -> str:
    return "OK"