Mysql sql查询：使用groupBy子句显示所有行

使用groupBy子句时是否可以显示所有表行？ 经验：

预期结果：按用户\u id计数后

id      user_id   gift_id   count 
 1        1          1       3
 2        1          2       3
 3        1          1       3
 4        2          3       2
 5        2          1       2
 6        3          4       1

试试这个

select a.*, b.user_count from tablename as a join 
(select user_id, count(*) as user_count from tablename group by user_id) as b on
a.user_id= b.user_id 

---

他不希望所有行合并

select a.*, b.user_count from tablename as a join 
(select user_id, count(*) as user_count from tablename group by user_id) as b on
a.user_id= b.user_id 

SELECT id
     , user_id
     , gift_id
     , Count(user_id) over (PARTITION BY user_id) nb_user_id
FROM matable