计算表列中的单词出现次数

Question

我有一个varchar(255)字段的表.我想(通过查询,函数或SP)获得此表中一组行中每个单词的出现次数.

如果这些字段有2行:

"I like to eat bananas"
"I don't like to eat like a monkey"

我想得到

    word | count()
    ---------------
    like  3
    eat   2
    to    2
    i     2
    a     1

任何的想法？我正在使用MySQL 5.2.

Answer 1

@Elad Meidar，我喜欢你的问题，我找到了一个解决方案：

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，我们执行一个查询来提取所有单词，如@peterm 所解释的（如果您想自定义处理的单词总数，请按照他的说明进行操作）。然后我们将其转换为子查询，然后我们 COUNT计算GROUP BY每个单词的值，然后在此基础上对GROUP BY可能存在伴随符号的未分组单词情况进行另一个查询。即：你好=你好！与一个REPLACE

Answer 2

我建议根本不要在 SQL 中执行此操作。您正在向数据库加载它不擅长的东西。选择一组行并在应用程序端进行频率计算将更容易实现，工作速度更快，并且维护时问题/麻烦更少。