Find rows that have the same value on a column in MySQL?

First, we will create a table and insert some values into the table. Let us create a table.

 mysql> create table RowValueDemo -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (0.69 sec) 

Insert records using the insert command. We have added duplicate values as well for our example.

 mysql> insert into RowValueDemo values('John'); Query OK, 1 row affected (0.14 sec) mysql> insert into RowValueDemo values('Bob'); Query OK, 1 row affected (0.14 sec) mysql> insert into RowValueDemo values('Carol'); Query OK, 1 row affected (0.11 sec) mysql> insert into RowValueDemo values('John'); Query OK, 1 row affected (0.24 sec) mysql> insert into RowValueDemo values('John'); Query OK, 1 row affected (0.09 sec) mysql> insert into RowValueDemo values('John'); Query OK, 1 row affected (0.10 sec) mysql> insert into RowValueDemo values('Bob'); Query OK, 1 row affected (0.09 sec) mysql> insert into RowValueDemo values('Bob'); Query OK, 1 row affected (0.18 sec) 

Displaying all records with the help of select statement.

 mysql> select *from RowValueDemo; 

Here is the output.

 +-------+ | Name | +-------+ | John | | Bob | | Carol | | John | | John | | John | | Bob | | Bob | +-------+ 8 rows in set (0.00 sec) 

Now, we ill get only the rows that have same value for column using the following query −

 mysql> select * from RowValueDemo where Name in ( -> select Name from RowValueDemo -> group by Name having count(*) > 1 -> ); 

The following is the output.

 +------+ | Name | +------+ | John | | Bob | | John | | John | | John | | Bob | | Bob | +------+ 7 rows in set (0.06 sec)