mongodb - mongo怎么导出一个内嵌数组中的某些信息

Question

比如这样

{
  "_id": 1,
  "array": [
    {"name": "a", "price": "2","amount":1},
    {"name": "b", "price": "2","amount":2},
    {"name": "c", "price": "3","amount":4}  
  ] 
}

我只想把name属性和price属性导出，该怎么做呢？用mongoexport貌似无法实现啊，诸位有什么好的办法吗？求教了

Answer 1

mongo supports js scripts, and you can use javascript scripts to batch process and export data:

#!/usr/bin/env mongo
db = db.getSiblingDB(db_name)
// db.auth("user", "passwd");

result = {};
db.clt_name.find().forEach(function(r) {
    // 这里是回调函数，r就是每一条记录，是一个object对象，可以遍历r.array，把需要的属性存入result
})

for (var key in result) {
    // 按照你希望的格式输出：
    print(key + "\t" + result[key])
}

For functions that can be used in the mongo environment, see Write Scripts for the mongo Shell