云数据库中集合的名称是“sfzs_taocan”，这个集合种的记录有四个字段，分别是“_id”、“neirong”、“qiyongriqi”、“yuexiaofei”，该集合的数据权限是：所有用户可读，仅创建者可读写。现在的需求是，在小程序端只显示“yuexiaofei”字段，代码如下：

const db = wx.cloud.database()；

 db.collection('sfzs_taocan').field({

            _id: false,

            neirong: false,

            qiyongriqi: false,

            yuexiaofei: true

        }).get()

            .then(res => {//请求成功

                console.log(res.data);

            })

            .catch(err => {//请求失败

                console.log('请求失败', err)

            });

执行后，出现错误提示：

请求失败 Error: errCode: -501007 invalid parameters | errMsg: [InvalidParameterValue.QueryProjection] Query projection entered in the request is illegal. Please check your request, but if the problem persists, contact us.

    at success (WASubContext.js?t=wechat&s=1649332451606&v=2.23.2:2)

    at Function.success (WAServiceMainContext.js:2)

    at d (WAServiceMainContext.js:2)

    at Object.success (WAServiceMainContext.js:2)

    at a (WAServiceMainContext.js:2)

    at WAServiceMainContext.js:2

    at Mi (WAServiceMainContext.js:2)

    at WAServiceMainContext.js:2

    at VM9 asdebug.js:1

    at C (VM9 asdebug.js:1)

各位大神，帮我看看，到底是什么问题。拜托了！