Editing Find and remove duplicates (section)

==== Finding duplicate value that differ in one column ====
'''Finding duplicate value that differ in one column'''<ref>[http://stackoverflow.com/questions/688549/finding-duplicate-values-in-mysql?rq=1 Finding duplicate values in MySQL - Stack Overflow]</ref>
<pre>
-- Generate test data.
CREATE TABLE `table_name` (
  `id` int(11) NOT NULL,
  `content` varchar(5) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `table_name` (`id`, `content`) VALUES
(1, 'apple'),
(2, 'lemon'),
(3, 'apple');

ALTER TABLE `table_name`
  ADD PRIMARY KEY (`id`);

-- Find duplicated data
SELECT `content`, COUNT(*) count 
FROM `table_name` 
GROUP BY `content` 
HAVING count > 1;

SELECT tmp.* FROM 
( 
  SELECT `content`, count(*) count FROM `table_name` GROUP BY `content` 
) tmp 
WHERE tmp.count >1;
</pre>

'''Another approach:''' Add {{kbd | key=content_hash}} column which its value is {{kbd | key=MD5(content_column)}}<ref>[https://errerrors.blogspot.com/2023/08/how-to-find-duplicate-text-values-in-mysql.html MySQL 如何尋找重複的文章 (文字類型資料)]</ref>

<pre>
-- To find the duplicated records with same content
SELECT count(*) as count, content_hash
FROM `YOUR_TABLE_NAME`
GROUP BY content_hash
HAVING count >= 2
</pre>