mongomongo_aggragate使用

Posted 2022-11-12 calinayc

1、分组后进行统计：使用$sum

db.zan.aggregate(["$match":"group_name":"班级名称","is_zan":"true","$group":"_id":"$stu_name","点赞数":"$sum":1]);

 

2、分组统计后进行排序：在group后使用$sort

db.zan.aggregate(["$match":"group_name":"班级名称","is_zan":"true","$group":"_id":"$stu_name","点赞数":"$sum":1,"$sort":"点赞数":-1]);

 

3、日期转化：时间戳转化为具体日期进行聚合

db.org.aggregate(["$group": "_id": "$dateToString": "format": "%Y-%m-%d","date": "$add": [new Date(0),"$create_time"],"新增开通机构数":"$sum":1, $sort: "_id" : -1 ]);

 

4、数组长度查询

db.group.aggregdate("$match": "name": "花花啊" ,"$project":"stulist":"$size":"$stulist");