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)

AmitDiwan

Published on 26-Aug-2019 06:37:17

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