查询以获取数据库表中给定单词的出现次数

Question

我在数据库中有以下表格。

users
-----------------
| id | username |
-----------------
|  1 | goje     |
|  2 | john     |
|  3 | henry    |
-----------------

comments
-------------------------------------------------
| id | uid |          comment                   |
-------------------------------------------------
|  1 |  1  | One who works hard is the one who  |
|    |     | succeeds                           |
|  2 |  1  | This one was the best.             |
|  3 |  2  | You are one of my best friends.    |
|  4 |  3  | He was the one who bought this one.|
-------------------------------------------------

现在，假设给定的单词是“one”。我想有一个MySQL查询，可以让我知道users表中每个用户出现的这个单词的数量。 在这种情况下，结果应该是

--------------------
| username | count |
--------------------
| goje     | 3     |   -> 2 in first comment and 1 in second
| henry    | 2     |   -> 2 in henry's only comment
| john     | 1     | 
--------------------

请告诉我如何使用SQL实现此目的。谢谢！

Answer 1

尝试此查询：

SELECT
 users.username AS username,
 round(sum((LENGTH(comments.comment) - LENGTH(REPLACE(LOWER(comments.comment),"one", ""))) / LENGTH("one")), 0) AS count
FROM users
 INNER JOIN comments ON comments.uid = users.id
GROUP BY users.id
ORDER BY count DESC;

我不知道REGEXP方法是否更便宜或更昂贵。