在MongoDB中检索数据

Question

{
    "ID" : 7,
    "vendor" : "Gold's Gym",
    "savings" : 50,
    "value" : 300,
    "description" : "Get a 3 month membership for $250 ($300 value)",
    "terms" : "Non transferrable",
    "product" : "Membership",
    "expires" : {
            "year" : 2017,
            "month" : 7,
            "date" : 31
    },
    "code" : "GYM-1",
    "tags" : [
            "fitness"
    ]
},
{
    "ID" : 8,
    "vendor" : "Golds Gym",
    "discount" : 15,
    "description" : "Get 15% discount on fitness classes",
    "terms" : "Non transferrable",
    "exceptions" : "Not applicable to swimming classes",
    "product" : "Classes",
    "purchaseValidity" : {
            "year" : 2017,
            "month" : 7,
            "date" : 31
    },
    "expires": {
            "year" : 2017,
            "month" : 12,
            "date" : 31
    },
    "code" : "GYM-2",
    "tags" : [
            "fitness"
    ]
}

这是拉格码的一部分。但是，我想检索带有标签的数据项:提供折扣的健身：$gte 10或超过10的储蓄。

这就是我开始使用的东西，但是我找不到可以同时使用折扣和健身的语法。

items.find({tags: "fitness"}, {discount: {$gte: 10}}).pretty()

Answer 1

你可以这样做:-

1.用于数组中匹配的$elemMatch。

2.$和默认情况下的查询。

items.find({ tags:{  $elemMatch:{$eq: "fitness"}} ,
             $or:[  {discount: {$gte: 10}},
                    {savings: {$gte: 10}} 
                 ] })

谢谢。