MySQL queries for all records that are not duplicated in a field _mysql

Suppose there are now the following N records indicating that the book is called
ID Author title
1 AAA AAA
2 BBB BBB
3 CCC CCC
4 DDD DDD
5 Eee AAA
Now you want to query all the title duplicates from these 5 records
Select DISTINCT Title,author from book this is not possible because distinct only works on one field
Want to ask how to write
Answer:

Copy Code code as follows:

Select A.* from Book a Right join (
Select MAX (ID) ID from book Group by Title B on b.id = a.ID
Where a.id is not null

If you choose the first match, then you can use min (id).

Copy Code code as follows:

Select A.* from Book a Right join (
Select min (id) ID from book Group by Title B on b.id = a.ID
Where a.id is not null