Question

您好我正在使用musicbrainz数据库，我无法计算每个国家的所有艺术家，但无论我尝试哪个国家，我都会得到相同的错误，即使我尝试使用喜欢。任何人都可以告诉我我做错了什么？

错误：列“％u％”不存在第7行：WHERE AREA.NAME类似于“％u％”

SELECT COUNT(artist.name)
FROM artist
JOIN area ON artist.area = area.id 
JOIN label ON area.id = label.area
JOIN country_area ON area.id = country_area.area
JOIN release_country ON country_area.area = release_country.country
WHERE AREA.NAME LIKE "%dom"
GROUP BY release_country.country
limit 5;

更新：

musicbrainz_db=> SELECT COUNT(artist.name)
musicbrainz_db-> FROM artist
musicbrainz_db-> JOIN area ON artist.area = area.id
musicbrainz_db-> JOIN label ON area.id = label.area
musicbrainz_db-> JOIN country_area ON area.id = country_area.area
musicbrainz_db-> JOIN release_country ON country_area.area = 
release_country.country
musicbrainz_db-> WHERE AREA.NAME LIKE '%dom'
musicbrainz_db-> GROUP BY release_country.country
musicbrainz_db-> limit 5;

错误：由于语句超时而取消语句

我的老师刚过来说它不会处理子查询？

select area.name, label_count
from area
where label_count in 
(
    select area.name, count(label.id) as "label_count"
    from area
    JOIN label on area.id = label.area
    group by area.name
);

子查询工作正常，但主查询失败？任何想法为什么。

Answer 1

SELECT COUNT(artist.name)
FROM artist
JOIN area ON artist.area = area.id 
JOIN label ON area.id = label.area
JOIN country_area ON area.id = country_area.area
JOIN release_country ON country_area.area = release_country.country
WHERE AREA.NAME LIKE '%u%'
GROUP BY release_country.country
limit 5;

Answer 2

参见MySQL官方文档

https://dev.mysql.com/doc/refman/5.7/en/string-comparison-functions.html

尝试使用单引号

SELECT COUNT(artist.name)
FROM artist
JOIN area ON artist.area = area.id 
JOIN label ON area.id = label.area
JOIN country_area ON area.id = country_area.area
JOIN release_country ON country_area.area = release_country.country
WHERE AREA.NAME LIKE '%dom'
GROUP BY release_country.country
limit 5;

双引号用于列名

musicbrainz无法按国家统计艺术家

2 个答案: