The following syntax is used in the console. Assume that there are collections (equivalent to relational database libraries) qyxxcx, documents (equivalent to tables) qyxx, jyzcjzs
show dbs
use qyxxcx
db
show collections
db.qyxx.drop()
db.qyxx.find()
db.qyxx.findOne()
db.qyxx.find({"Name": "abcd"})
db.qyxx.aggregate([{$lookup:{from: "yjzcjzs",localField:"CORP_NAME",foreignField:"qymc",as:"jzs"}}])