mysql - MYSQL 选择重复的行，其中重复 2 或 3 列值

Question

由于 Ajax 错误，我最终得到了大量重复数据，其中 2 列的组合需要是唯一的。name我为surname这个问题简化了表格。

想象一下在表users中我怎样才能得到+被重复的id地方。我附上了一张图片。namesurname

Answer 1

SELECT id, name, surname FROM users t1 WHERE 
  EXISTS(SELECT id FROM users t2 
            WHERE t1.id <> t2.id AND 
                  t1.name = t2.name AND 
                  t1.surname = t2.surname)

Answer 2

尝试这个

select Id from  users u inner join 
(SELECT  name,surname,count(*) cnt FROM  users GROUP BY name,surname 
HAVING cnt >1) dup on dup.name = u.name and u.surname = dup.surname 

见 SQL 小提琴