MySql：计算单词在列中出现的次数

Question

例如，如果我在这样的列中有数据

data
I love book
I love apple
I love book
I hate apple
I hate apple

我怎样才能得到这样的结果

I = 5
love = 3
hate = 2
book = 2
apple = 3

我们可以用 MySQL 来实现吗？

Answer 1

这是仅使用查询的解决方案：

SELECT SUM(total_count) as total, value
FROM (

SELECT count(*) AS total_count, REPLACE(REPLACE(REPLACE(x.value,'?',''),'.',''),'!','') as value
FROM (
SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(t.sentence, ' ', n.n), ' ', -1) value
  FROM table_name t CROSS JOIN 
(
   SELECT a.N + b.N * 10 + 1 n
     FROM 
    (SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a
   ,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b
    ORDER BY n
) n
 WHERE n.n <= 1 + (LENGTH(t.sentence) - LENGTH(REPLACE(t.sentence, ' ', '')))
 ORDER BY value

) AS x
GROUP BY x.value

) AS y
GROUP BY value

这是完整的工作小提琴：http ://sqlfiddle.com/#!2/ 17481a/1

首先，我们做一个查询，提取所有的字作为解释这里的@peterm（按照他的指示，如果你想自定义处理的字的总数）。然后我们将其转换为子查询，然后我们 COUNT和GROUP BY每个单词的值，然后在此基础上进行另一个查询，以GROUP BY不将可能存在伴随符号的单词分组。即：你好=你好！与REPLACE