Question

如何查询子文档中的子文档。？

如何在商业文件中检索城市名称。

{
    "_id" : " c2 ",
    "commercial" : {
        " type " : " restaurant ",
        " sale_type " : " sale ",
        " owner_name " : " josi schmit",
        " address " : {
            " street " : " kleine rittergasse ",
            " plot_no " : 4,
            " city " : " frankfurt ",
            " state " : " hessen ",
            " country " : "germany ",
            "postal_code " : 60329,
            "email" : " josi123@gmail.com"
        },
        " total_area " : " 300 sq meters ",
        " sale_price(EUR) " : 100000,
        " features " : {
            " lifts " : 1,
            " heating " : true,
            " parking " : true,
            " kitchen " : true,
            " security_cameras " : true,
            " furniture " : true
        }
    }
}

这是我的查询，但我知道我错了请帮助我。

db.property.find（{“_ id”：“c2”，“address.city”：“c2”}）

此致斯里卡特

Answer 1

Actualy有两种方法可以做到：

db.property.find ( { "_id": "c2", "commercial.address.city": "c2" }, {"commercial.address.city": true} )
db.property.find ( { "_id": "c2", "commercial": { "address" : { "city": "c2" }}} )

两种情况的区别在于，在第一种情况下，如果您有索引index，则mongo将跟随commercial.address.city，而第二种情况则不会，因此我会使用第一种

如何在mongodb中查询子文档？

1 个答案: