mongodb - Mongodb中的“未知顶级运算符：$ OR”错误

Question

我尝试运行此查询以获取 PostGraduate 和 Graduate 文档的计数。我收到错误消息：“errmsg”：“未知顶级运算符：$OR”请告诉我这里的错误是什么。

db.collection.aggregate(
[
{ "$match": { "$OR": 
[{Education: "Graduate"}, {Education: "PostGraduate"}] 
} },
{ $group: { _id: "$Education",  TotalCount: { $sum: 1 } } }
]
)

这是集合：

{ Education: "Graduate" },
{ Education: "Graduate" },
{ Education: "Graduate" },
{ Education: "PostGraduate" },
{ Education: "PostGraduate" },
{ Education: "UnderGraduate" },
{ Education: "UnderGraduate" }

标签： mongodbmatchpipelineaggregation