Find duplicate column values in MySQL and display them

For this, use GROUP BY HAVING clause. Let us first create a table −

mysql> create table DemoTable1858      (      ModelNumber varchar(50)      ); Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1858 values('Audi A4'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1858 values('Audi A6'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1858 values('Audi A4'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1858 values('Audi Q5'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1858 values('Audi R8'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1858 values('Audi Q5'); Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1858; 

This will produce the following output −

+-------------+ | ModelNumber | +-------------+ | Audi A4     | | Audi A6     | | Audi A4     | | Audi Q5     | | Audi R8     | | Audi Q5     | +-------------+ 6 rows in set (0.00 sec)

Here is the query to find duplicate column value in MySQL −

mysql> select ModelNumber from DemoTable1858      group by ModelNumber      having count(ModelNumber) >=2;

This will produce the following output −

+-------------+ | ModelNumber | +-------------+ | Audi A4     | | Audi Q5     | +-------------+ 2 rows in set (0.00 sec)