Question

我的应用使用带有locationId，scoreDateTime，得分和评论列的得分表。用户可以为位置评分并可选择提交评论。小数据集可能如下所示：

mysql> select locationId, scoreDateTime, score, comments from scores;
+-----------------------------+-------------------------+-------+--------------------------------+
| locationId                  | scoreDateTime           | score | comments                       |
+-----------------------------+-------------------------+-------+--------------------------------+
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 17:30:32.899 |     3 | asdfasf                        |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 18:28:46.221 |     3 |                                |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 18:29:56.395 |     3 | safasf                         |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 18:32:10.358 |     3 |                                |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 18:49:32.262 |     3 |                                |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 18:50:33.693 |     3 |                                |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 19:13:58.456 |     3 |                                |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ | 2016-04-17 19:28:10.435 |     3 | asdfasf                        |
| ChIJqZyf8O8F44kRhatfHL4GYe0 | 2016-04-17 23:20:28.857 |     3 | aasdfasfsfsd                   |
| ChIJqZyf8O8F44kRhatfHL4GYe0 | 2016-04-17 23:22:55.254 |     3 | asdfasfasfsafasfsfasf asdfasfd |
| ChIJqZyf8O8F44kRhatfHL4GYe0 | 2016-04-17 23:40:37.106 |     3 |                                |
| ChIJpbSR1a4I44kRemEzTpniis8 | 2016-04-19 11:17:41.836 |     5 | adfgadf                        |
| ChIJF1LAoqgI44kR5EWvRqJPUN4 | 2016-04-19 11:17:52.536 |     4 |                                |
+-----------------------------+-------------------------+-------+--------------------------------+

我想构建一个查询，为每个位置获取以下内容：

过去X小时的分数
过去Y天的评论数
过去Y天内任何评论的最新得分数字时间（或NULL）

我的动机是显示地点，最近的分数，历史评论数以及最新评论日期时间（或null）。这将给我最近的跑分数和评论线的热度。

以下查询有效。但是，重复的locationId列表实际上会在生产中高得多。 问题：我想知道是否有一种高效的方法来合并2个locationId列表，a.k.a'positionId in（...）'。

select
   x.locationId, count1, count2, count3, count4, count5, IFNULL(commentCount,0) as commentCount, lastCommentDateTime
from

   ( select
        locationId,
        sum(if (score = 1, 1, 0)) count1,
        sum(if (score = 2, 1, 0)) count2,
        sum(if (score = 3, 1, 0)) count3,
        sum(if (score = 4, 1, 0)) count4,
        sum(if (score = 5, 1, 0)) count5
     from
        scores
     where
        scoreDateTime > '2016-04-16 21:38:51.843' and
        locationId in (
           'ChIJqZyf8O8F44kRbNWHQkDkpGQ',
           'ChIJqZyf8O8F44kRhatfHL4GYe0',
           'ChIJCes00a4I44kRKG8zB4KvYTM',
           'ChIJP-eRLq8I44kRKU6VOpTXqTM',
           'ChIJpbSR1a4I44kRemEzTpniis8',
           'ChIJF1LAoqgI44kRip2l7rjO2g4',
           'ChIJF1LAoqgI44kR5EWvRqJPUN4',
           'ChIJF1LAoqgI44kRRD_ZvPUmrGA',
           'ChIJjweq4h0G44kRWoCPQKPdrPM',
           'ChIJf2tVDB4G44kRTYjhl3sjm8M',
           'ChIJ_Vg4giEG44kRq2nvtjEn8yA',
           'ChIJP00qFSMG44kRyKcy2f_S12o'
        )
     group by locationId
   ) as x

left join

   ( select
        locationId,
        count(comments) as commentCount,
        max(scoreDateTime) as lastCommentDateTime
     from
        scores
     where
        comments != "" and
        scoreDateTime > '2016-01-16 00:00:00.000' and
        locationId in (
           'ChIJqZyf8O8F44kRbNWHQkDkpGQ',
           'ChIJqZyf8O8F44kRhatfHL4GYe0',
           'ChIJCes00a4I44kRKG8zB4KvYTM',
           'ChIJP-eRLq8I44kRKU6VOpTXqTM',
           'ChIJpbSR1a4I44kRemEzTpniis8',
           'ChIJF1LAoqgI44kRip2l7rjO2g4',
           'ChIJF1LAoqgI44kR5EWvRqJPUN4',
           'ChIJF1LAoqgI44kRRD_ZvPUmrGA',
           'ChIJjweq4h0G44kRWoCPQKPdrPM',
           'ChIJf2tVDB4G44kRTYjhl3sjm8M',
           'ChIJ_Vg4giEG44kRq2nvtjEn8yA',
           'ChIJP00qFSMG44kRyKcy2f_S12o'
        )
     group by locationId
   ) as y

on x.locationId = y.locationId;

结果如下所示：

mysql> source ../../query3.sql
+-----------------------------+--------+--------+--------+--------+--------+--------------+-------------------------+
| locationId                  | count1 | count2 | count3 | count4 | count5 | commentCount | lastCommentDateTime     |
+-----------------------------+--------+--------+--------+--------+--------+--------------+-------------------------+
| ChIJF1LAoqgI44kR5EWvRqJPUN4 |      0 |      0 |      0 |      1 |      0 |            0 | NULL                    |
| ChIJpbSR1a4I44kRemEzTpniis8 |      0 |      0 |      0 |      0 |      1 |            1 | 2016-04-19 11:17:41.836 |
| ChIJqZyf8O8F44kRbNWHQkDkpGQ |      0 |      0 |      8 |      0 |      0 |            3 | 2016-04-17 19:28:10.435 |
| ChIJqZyf8O8F44kRhatfHL4GYe0 |      0 |      0 |      3 |      0 |      0 |            2 | 2016-04-17 23:22:55.254 |
+-----------------------------+--------+--------+--------+--------+--------+--------------+-------------------------+

Answer 1

您的2个查询之间的区别似乎是comments和select条件。组合查询的一种方法是使用条件聚合将这些条件移动到sum。

此外，mysql会将布尔值评估为1或0，因此您可以通过删除if语句来简化select locationId, sum(score = 1 and scoreDateTime > '2016-04-16 21:38:51.843') count1, sum(score = 2 and scoreDateTime > '2016-04-16 21:38:51.843') count2, sum(score = 3 and scoreDateTime > '2016-04-16 21:38:51.843') count3, sum(score = 4 and scoreDateTime > '2016-04-16 21:38:51.843') count4, sum(score = 5 and scoreDateTime > '2016-04-16 21:38:51.843') count5, sum(comments != "") commentCount, max(case when comments != "" then scoreDateTime end) as lastCommentDateTime from scores where scoreDateTime > '2016-01-16 00:00:00.000' and locationId in ( 'ChIJqZyf8O8F44kRbNWHQkDkpGQ', 'ChIJqZyf8O8F44kRhatfHL4GYe0', 'ChIJCes00a4I44kRKG8zB4KvYTM', 'ChIJP-eRLq8I44kRKU6VOpTXqTM', 'ChIJpbSR1a4I44kRemEzTpniis8', 'ChIJF1LAoqgI44kRip2l7rjO2g4', 'ChIJF1LAoqgI44kR5EWvRqJPUN4', 'ChIJF1LAoqgI44kRRD_ZvPUmrGA', 'ChIJjweq4h0G44kRWoCPQKPdrPM', 'ChIJf2tVDB4G44kRTYjhl3sjm8M', 'ChIJ_Vg4giEG44kRq2nvtjEn8yA', 'ChIJP00qFSMG44kRyKcy2f_S12o' ) group by locationId次调用。

(locationId, scoreDateTime)

此查询可以利用SELECT * FROM mytable WHERE INSTR(:value, name) > 0

上的综合索引

使用具有相同where子句的2个子选择合并SQL查询

1 个答案: