试着使用这个查询:

SELECT name, COUNT(*) value_count FROM company_master GROUP BY name HAVING value_count > 1;

我看到上面的结果和查询将工作良好，如果你需要检查单列值是重复的。比如电子邮件。

但如果你需要检查更多的列，并希望检查结果的组合，那么这个查询将正常工作:

SELECT COUNT(CONCAT(name,email)) AS tot,
       name,
       email
FROM users
GROUP BY CONCAT(name,email)
HAVING tot>1 (This query will SHOW the USER list which ARE greater THAN 1
              AND also COUNT)

我从下面开始改进:

SELECT 
    col, 
    COUNT(col)
FROM
    table_name
GROUP BY col
HAVING COUNT(col) > 1; 

根据levik的回答来获取重复行的id，如果服务器支持的话，可以执行GROUP_CONCAT(这将返回一个以逗号分隔的id列表)。

SELECT GROUP_CONCAT(id), name, COUNT(*) c
FROM documents
GROUP BY name
HAVING c > 1;

SELECT * 
FROM `dps` 
WHERE pid IN (SELECT pid FROM `dps` GROUP BY pid HAVING COUNT(pid)>1)

我更喜欢使用窗口函数(MySQL 8.0+)来查找副本，因为我可以看到整行:

WITH cte AS (
  SELECT *
    ,COUNT(*) OVER(PARTITION BY col_name) AS num_of_duplicates_group
    ,ROW_NUMBER() OVER(PARTITION BY col_name ORDER BY col_name2) AS pos_in_group
  FROM table
)
SELECT *
FROM cte
WHERE num_of_duplicates_group > 1;

DB小提琴演示