mongo：如何检索与类型为数字或数组的字段完全匹配的文档？答案

【问题标题】：mongo: how to retrieve the document exactly matching a field whose type is number or array?mongo：如何检索与类型为数字或数组的字段完全匹配的文档？
【发布时间】：2020-02-20 16:22:25
【问题描述】：

我有以下收藏：

{ "_id" : ObjectId("5e4e3e068438c24cdec0eeb9"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eeba"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc", "efg" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebb"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : "0xmd5md5md5" }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebc"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123 ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebd"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : 123 }

“extraid”字段是数字或数组，当我在下面运行操作时，返回的结果不是我想要的：

> db.foo.find({"extraid": 123})
{ "_id" : ObjectId("5e4e3e068438c24cdec0eeb9"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eeba"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc", "efg" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebc"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123 ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebd"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : 123 }

我认为只有一个文档匹配，这是我的预期结果：

{ "_id" : ObjectId("5e4e3e078438c24cdec0eebd"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : 123 }

我也尝试运行$type 运算符，以便它可以完全匹配，但结果仍然不是我想要的：

> db.foo.find({"extraid": {"$eq": 123, "$type":"int"}})
{ "_id" : ObjectId("5e4e3e068438c24cdec0eeb9"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eeba"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc", "efg" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebc"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123 ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebd"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : 123 }
> db.foo.find({"extraid": {"$eq": 123, "$type":"array"}})
{ "_id" : ObjectId("5e4e3e068438c24cdec0eeb9"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eeba"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123, "abc", "efg" ] }
{ "_id" : ObjectId("5e4e3e078438c24cdec0eebc"), "from" : "0xabsdfeeqwsfdasfafaefegr", "to" : "0xfdshshrtfafdfadfaete", "extraid" : [ 123 ] }
>

$type: array可以匹配所有'extraid'的数组类型，但是$type: int不行。

那么谁知道如何检索与类型为数字或数组的字段完全匹配的文档？

【问题讨论】：

标签： mongodb mongodb-query

【解决方案1】：

您可以尝试以下查询：

db.foo.find({$expr : {$and : [{$eq : ['int', {$type :'$extraid'}]}, {$eq : ["$extraid", 123]}]}})

注意：检查extraid字段中的数据，然后根据需要使用double而不是int。

收集中的数据：

/* 1 */
{
    "_id" : ObjectId("5e4e3e068438c24cdec0eeb9"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : [ 
        123.0, 
        "abc"
    ]
}

/* 2 */
{
    "_id" : ObjectId("5e4e3e078438c24cdec0eeba"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : [ 
        123.0, 
        "abc", 
        "efg"
    ]
}

/* 3 */
{
    "_id" : ObjectId("5e4e3e078438c24cdec0eebb"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : "0xmd5md5md5"
}

/* 4 */
{
    "_id" : ObjectId("5e4e3e078438c24cdec0eebc"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : [ 
        123.0
    ]
}

/* 5 */
{
    "_id" : ObjectId("5e4e3e078438c24cdec0eebd"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : 123
}

/* 6 */
{
    "_id" : ObjectId("5e4e3e078438c24cdec0ee11"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : 12301
}

输出：

{
    "_id" : ObjectId("5e4e3e078438c24cdec0eebd"),
    "from" : "0xabsdfeeqwsfdasfafaefegr",
    "to" : "0xfdshshrtfafdfadfaete",
    "extraid" : 123
}

【讨论】：