MongoDB小结19

利用all来查询所以满足的匹配项,已知数据库有这些数据

db.user.find({},{"_id":0})
{ "fruit" : [ "apple", "banana", "cherry" ] }
{ "fruit" : [ "apple", "banana", "pear" ] }
{ "fruit" : [ "apple", "watermelon", "pear" ] }

需要查询出有apple和cherry的文档

db.user.find({"fruit":{$all:["apple","cherry"]}},{"_id":0})
{ "fruit" : [ "apple", "banana", "cherry" ] }

与之前的OR查询（$or $in）相比，$all的查询模式更像是去取交集，即同时满足查询条件才能被查询出来。