MySQL query to select the values having multiple occurrence and display their count

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

mysql> create table DemoTable673(    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Value int ); Query OK, 0 rows affected (0.59 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable673(Value) values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable673(Value) values(20); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable673(Value) values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable673(Value) values(30); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable673(Value) values(20); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable673(Value) values(10); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable673(Value) values(10); Query OK, 1 row affected (0.28 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable673;

This will produce the following output −

+----+-------+ | Id | Value | +----+-------+ | 1 | 10 | | 2 | 20 | | 3 | 10 | | 4 | 30 | | 5 | 20 | | 6 | 10 | | 7 | 10 | +----+-------+ 7 rows in set (0.00 sec)

Following is the query to display only the values having multiple occurrences −

mysql> select Id,count(*) as myValue from DemoTable673 group by Value having count(*) > 1;

This will produce the following output −

+----+---------+ | Id | myValue | +----+---------+ | 1 | 4 | | 2 | 2 | +----+---------+ 2 rows in set (0.00 sec)