mongodb - 如何在Mongodb中单独查询数组中的项目

Question

我的收藏名称是employee，我的收藏如下

{
   "Title":"IssueFixingTeam",
   "TeamLead":"Mr.Bean",
   "workers":["xxx","yyy","zzz"]
 },

{
   "Title":"DevelopmentTeam",
   "TeamLead":"Mr.John Doe",
   "workers":["aa","dd","ss"]
 }

如何查询查找，TeamLead“憨 bean 先生”下有多少 worker 提前致谢

Answer 1

如果您只对属于“Mr.Bean”的一条记录感兴趣(否则，请参阅@felix 的回答)，那么这可以为您提供所需的计数:

db.employee.findOne({'TeamLead': 'Mr.Bean'}).workers.length