如何在MySQL中找到最流行的单词出现？

Question

我有一个叫results5列的表.

我想使用该title列来查找所说的行:WHERE title like '%for sale%'然后列出该列中最常用的单词.一个会是for另一个会是,sale但我想看看其他单词与此相关.

样本数据:

title
cheap cars for sale
house for sale
cats and dogs for sale
iphones and androids for sale
cheap phones for sale
house furniture for sale

结果(单个单词):

for    6
sale    6
cheap    2
and    2
house    2
furniture 1
cars    1
etc...

Answer 1

您可以通过一些字符串操作来提取单词.假设您有一个数字表,并且单词由单个空格分隔:

select substring_index(substring_index(r.title, ' ', n.n), ' ', -1) as word,
       count(*)
from results r join
     numbers n
     on n.n <= length(title) - length(replace(title, ' ', '')) + 1
group by word;

如果您没有数字表,可以使用子查询手动构建一个:

from results r join
     (select 1 as n union all select 2 union all select 3 union all . . .
     ) n
     . . .

SQL Fiddle(由@GrzegorzAdamKowalski提供)就在这里.

Answer 2

您可以以某种有趣的方式使用 ExtractValue。请参阅此处的 SQL 小提琴： http 45

我们只需要一张桌子：

CREATE TABLE text (`title` varchar(29));

INSERT INTO text (`title`)
VALUES
    ('cheap cars for sale'),
    ('house for sale'),
    ('cats and dogs for sale'),
    ('iphones and androids for sale'),
    ('cheap phones for sale'),
    ('house furniture for sale')
;

现在我们构造一系列选择，从转换为 XML 的文本中提取整个单词。每个选择从文本中提取第 N 个单词。

select words.word, count(*) as `count` from
(select ExtractValue(CONCAT('<w>', REPLACE(title, ' ', '</w><w>'), '</w>'), '//w[1]') as word from `text`
union all
select ExtractValue(CONCAT('<w>', REPLACE(title, ' ', '</w><w>'), '</w>'), '//w[2]') from `text`
union all
select ExtractValue(CONCAT('<w>', REPLACE(title, ' ', '</w><w>'), '</w>'), '//w[3]') from `text`
union all
select ExtractValue(CONCAT('<w>', REPLACE(title, ' ', '</w><w>'), '</w>'), '//w[4]') from `text`
union all
select ExtractValue(CONCAT('<w>', REPLACE(title, ' ', '</w><w>'), '</w>'), '//w[5]') from `text`) as words
where length(words.word) > 0
group by words.word
order by `count` desc, words.word asc