在MongoDB中根据字段的数量类型来查询数据使用$type操作符来实现，具体使用法语：

1	db.集合名.find({$type:类型值})    //这里的类型值能使用Number也能使用alias

举个例子：

1 2	db.person.find({address:{$type:2}})         //查询address字段数据类型为字符串 db.person.find({address:{$type:"string"}})  //查询address字段数据类型为字符串

$type 有效的类型值，如下：

Type	Number	Alias	Notes
Double	1	“double”
String	2	“string”
Object	3	“object”
Array	4	“array”
Binary data	5	“binData”
Undefined	6	“undefined”	Deprecated.
ObjectId	7	“objectId”
Boolean	8	“bool”
Date	9	“date”
Null	10	“null”
Regular Expression	11	“regex”
DBPointer	12	“dbPointer”	Deprecated.
JavaScript	13	“javascript”
Symbol	14	“symbol”	Deprecated.
JavaScript (with scope)	15	“javascriptWithScope”
32-bit integer	16	“int”
Timestamp	17	“timestamp”
64-bit integer	18	“long”
Decimal128	19	“decimal”	New in version 3.4.
Min key	-1	“minKey”
Max key	127	“maxKey”

官网参考：https://docs.mongodb.com/manual/reference/operator/query/type/index.html

原文转自: http://www.xuexiyuan.cn/article/detail/107.html