MySQL-使用多个表按天选择过去7天的最后一个值
以下是我当前的数据库:MySQL-使用多个表按天选择过去7天的最后一个值,mysql,sql,date,statistics,inner-join,Mysql,Sql,Date,Statistics,Inner Join,以下是我当前的数据库: TABLE profileData +---------------------------+ | profileID | name | +----+----------------------+ | 1 | Stackoverflow | | 2 | Stackexchange | | 3 | Askubuntu | +-----------+---------------+ TABLE sta
TABLE profileData
+---------------------------+
| profileID | name |
+----+----------------------+
| 1 | Stackoverflow |
| 2 | Stackexchange |
| 3 | Askubuntu |
+-----------+---------------+
TABLE stats
+----+-----------+------------------------------+
| id | profileID | sCount | ts |
+----+-----------+--------+---------------------+
| 1 | 1 | 1 | 2013-10-04 00:00:01 |
| 2 | 2 | 5 | 2013-10-04 00:00:01 |
| 3 | 3 | 8 | 2013-10-04 00:00:01 |
| 4 | 1 | 10 | 2013-10-05 00:00:01 |
| 5 | 2 | 50 | 2013-10-05 00:00:01 |
| 6 | 1 | 100 | 2013-10-06 00:00:01 |
| 7 | 2 | 500 | 2013-10-06 00:00:01 |
| 8 | 1 | 101 | 2013-10-06 13:00:01 |
| 9 | 2 | 501 | 2013-10-06 19:00:01 |
| 10 | 3 | 17 | 2013-10-06 05:00:01 |
| 11 | 1 | 100 | 2013-10-09 00:00:01 |
| 12 | 2 | 500 | 2013-10-09 00:00:01 |
+----+-----------+------- +---------------------+
TABLE users
+--------+-----------+
| userID | profileID |
+--------------------+
| 1337 | 1 |
| 1337 | 2 |
+--------+-----------+
我需要的是:
从“用户”表中选择所有配置文件,并从“统计”表中获取过去7天内这些配置文件的名称+每天的最后一个条目。因此,预期的结果是
+---------------+--------+---------------------+
| name | sCount | ts |
+---------------+--------+---------------------+
| Stackoverflow | 1 | 2013-10-04 00:00:01 |
| Stackexchange | 5 | 2013-10-04 00:00:01 |
| Stackoverflow | 10 | 2013-10-05 00:00:01 |
| Stackexchange | 50 | 2013-10-05 00:00:01 |
| Stackoverflow | 101 | 2013-10-06 13:00:01 |
| Stackexchange | 501 | 2013-10-06 19:00:01 |
| Stackoverflow | 100 | 2013-10-09 00:00:01 |
| Stackexchange | 500 | 2013-10-09 00:00:01 |
+---------------+--------+---------------------+
我最后说了这样一句话:
SELECT
profileData.name,
stats.scount,
stats.ts
FROM
users
INNER JOIN profiles ON
users.profileID = profiles.profileID
INNER JOIN
(
SELECT t1.profileID, t1.sCount, t1.ts
FROM stats t1
INNER JOIN (
SELECT MAX(ts) maxi
FROM stats
GROUP BY DATE(ts)
) a2 ON t1.ts = a2.maxi) stats ON
users.profileID = stats.profileID
WHERE
users.userID = 1337 AND DATE(stats.ts) >= DATE(DATE_SUB(NOW(), INTERVAL 7 DAY))
ORDER BY users.userID, stats.ts
这部分起了作用。然而,这句话似乎有点过火了,它已经不起作用了
我还尝试选择了MAX(ts)
。这是可行的,但结果不包含相应的scont
值
所以,我正在寻找解决我问题的方法,我希望,任何人都能帮助我
哦,如果可能的话,它必须是一个纯SQL解决方案。您可以做类似的事情,这与您所做的并不遥远
select p.name,
s.scount,
s.ts
from profileData p
inner join users u on u.profileID = p.profileID
inner join stats s on s.profileID = p.profileID
inner join (select max(ts) as maxTs, profileID
from stats
where DATE(stats.ts) >= DATE(DATE_SUB(NOW(), INTERVAL 7 DAY))
group by profileID, DATE(ts)) as mx
on s.profileID = mx.profileID and mx.maxTs = s.ts
where u.userID = 1337
请参见关于这一点(解释更好),因为需要更少的完整表格扫描。。
但你真的需要索引
SELECT
profileData.name
, stats.sCount
, MAX(ts) ts
FROM
stats
INNER JOIN
users
ON
stats.profileID = users.profileID
INNER JOIN
profileData
ON
users.profileID = profileData.profileID
WHERE
users.userID = 1337
AND
DATE(stats.ts) >= DATE(DATE_SUB(NOW(), INTERVAL 7 DAY))
GROUP BY
profileData.name
, stats.profileID ASC
, stats.sCount ASC
ORDER BY
ts ASC
;
请参见演示哦,哇。这似乎真的奏效了,只是证实了我的“过度杀戮”是正确的。Tyvm.GROUP BY不应该是
stats.profileID,DATE(ts)
?不过,谢谢你。这是正确的,请看这里,这是不对的。。profileData.name将是随机的,并可能导致错误的值。。这是您应该始终使用sql\u mode=ONLY\u FULL\u GROUP\u BY…配置MySQL服务器的方式。。。