[
{ item: "journal", qty: 25, size: { h: 14, w: 21, uom: "cm" }, status: "A" }, #1
{ item: "notebook", qty: 50, size: { h: 8.5, w: 11, uom: "in" }, status: "A" }, #2
{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" }, #3
{ item: "planner", qty: 75, size: { h: 22.85, w: 30, uom: "cm" }, status: "D" }, #4
{ item: "postcard", qty: 45, size: { h: 10, w: 15.25, uom: "cm" }, status: "A" } #5
]
1.查找size
节点为{ h: 14, w: 21, uom: "cm" }
的doc,必须完全相同
{ size: { h: 14, w: 21, uom: "cm" } }
- >1
2.查找size
节点下h
节点值为14的doc,必须完全相同
{ "size.h": 14 }
-> 1
3.查找qyt
几点小于30的doc
{ "qyt": { $lt: 30 } }
- > 1
4.三个节点同时满足查询条件
{ "size.h": { $lt: 15 }, "size.uom": "in", status: "D" }
->{ item: "paper", qty: 100, size: { h: 8.5, w: 11, uom: "in" }, status: "D" }
参考:
https://docs.mongodb.com/manual/tutorial/query-embedded-documents/