我需要将 2700 万行表和 700 万行表中的信息结合起来并进行一些过滤。
CREATE TABLE event_participation (
place_id int(4),
person_id varchar(12),
event_id varchar(10),
event_description varchar(230),
.... and more fields about that specific participation
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE INDEX IDX_1 ON event_participation (place_id);
CREATE INDEX IDX_2 ON event_participation (person_id);
CREATE INDEX IDX_3 ON event_participation (event_id);
CREATE TABLE person (
person_id varchar(12),
last_name varchar(25),
first_name varchar(20),
middle_name varchar(20),
person_attr1 varchar(20),
...
person_attr50 varchar(20),
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE INDEX IDX_10 ON person (person_id);
CREATE INDEX IDX_11 ON person (person_attr1);
CREATE INDEX IDX_12 ON person (person_attr2);
...
我对查询中使用的所有属性都有索引。
event_participation表有2700万行,person表有700万行。
我需要运行这样的查询:
SELECT person.last_name, person.first_name
FROM event_participation
LEFT JOIN person ON event_participation.person_id = person.person_id
WHERE event_id IN ("event 1", "event 2", "event 3", "event 4",
"event 5", "event 6", "event 7") AND person.person_attr1 = 'A' AND
person.person_attr2 = 'B' AND place_id = 90
GROUP BY event_participation.person_id
HAVING count(event_id) >= 3
解释为:
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: event_participation
type: ref
possible_keys: person_id,event_id,place_id
key: place_id
key_len: 5
ref: const
rows: 6437170
Extra: Using where; Using temporary; Using filesort
*************************** 2. row ***************************
id: 1
select_type: SIMPLE
table: person
type: ref
possible_keys: person_id,person_attr1,person_attr2
key: person_id
key_len: 39
ref: event_participation.person_id
rows: 1
Extra: Using where
我正在寻找参加列表中至少 3 项事件并满足其他一些标准的活跃人士。通常我会修复与事件相关的标准,并运行多个仅改变人员属性的查询。
即使对于非常小的子集,此查询也非常慢,因此我寻找替代方法。 我创建一个缓存表:
CREATE TABLE temp_name (
person_id varchar(12),
PRIMARY KEY (person_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
运行如下查询:
INSERT INTO temp_name ( temp_name )
SELECT DISTINCT event_participation.person_id
FROM event_participation
WHERE event_id IN ("event 1", "event 2", "event 3", "event 4",
"event 5", "event 6", "event 7") AND place_id = 90
GROUP BY event_participation.person_id
HAVING count(event_id) >= 3
然后运行过滤器查询,例如:
SELECT person.last_name, person.first_name
FROM temp_name LEFT JOIN person ON temp_name.person_id = person.person_id
WHERE person.person_attr1 = 'A' AND person.person_attr2 = 'B'
虽然我可以接受最终查询的当前性能,但临时表的创建和管理却让我很痛苦。任何建议都将受到高度赞赏。
最佳答案
你能尝试一下吗:
SELECT person.last_name, person.first_name
FROM person pers
INNER JOIN
(SELECT person_id, count(*) as count
FROM event_participation
WHERE event_id IN ("event 1", "event 2", "event 3", "event 4",
"event 5", "event 6", "event 7") AND person.person_attr1 = 'A' AND
person.person_attr1 = 'B' AND place_id = 90
Group by person_id
) as event_count on event_count.person_id = pers.person_id AND event_count.count>2
更新:我忘记将分组依据添加到内部查询。
关于mysql - 非常大的表 JOIN 与 GROUP BY,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29876271/