Question

MySQL是否有办法按＆＃34;仅＃34;表中的连接（序列化）行：

ex，table：

id     user_id     score
1         1        100
2         1        100
3         2        100
5         1        100
7         1        100
8         3        100
9         4        100
10        5        100
10        5        100
11        1        100

分组＆＃34; user_id＆＃34;和sum(score)但仅适用于具有相同＆＃34; user_id＆＃34;的后续行，预期结果：

user_id     score
    1        200
    2        100
    1        200
    3        100
    4        100
    5        200
    1        100

测试查询：

select t.user_id,sum(t.score)
from table t
group by t.user_id

会返回类似的内容：

user_id     score
    1        500
    2        100
    3        100
    4        100
    5        200

谢谢，求助，

Answer 1

MariaDB [sandbox]> select user_id,sum(score) score
    -> from
    -> (select user_id,score,
    ->  if(user_id <> @p , @block:=@block+1,@block:=@block) block,
    ->  @p:=user_id
    -> from(select @block:=0,@p:=0) vars, t
    -> order by id,user_id
    -> ) s
    -> group by block
    ->  ;
+---------+-------+
| user_id | score |
+---------+-------+
|       1 |   200 |
|       2 |   100 |
|       1 |   200 |
|       3 |   100 |
|       4 |   100 |
|       5 |   200 |
|       1 |   100 |
+---------+-------+
7 rows in set (0.13 sec)

Answer 2

因为它是mysql，所以为分数增加id - description - title - id - user - authent - rel_id 1 - des1 - tit1 - 6 - admin - 4 - 5 2 - des2 - tit2 - null - null - null - null

group by

对于downvoters，check it

MySQL：仅按连接的行

2 个答案: