MySQL query to count occurrences of distinct values and display the result in a new column?

Let us first create a table −

mysql> create table DemoTable
(
   Value int
);
Query OK, 0 rows affected (0.57 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values(80);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values(90);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable values(90);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values(80);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable values(100);
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values(90);
Query OK, 1 row affected (0.12 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-------+
| Value |
+-------+
|    80 |
|    90 |
|    90 |
|    80 |
|    100|
|    90 |
+-------+
6 rows in set (0.00 sec)

Following is the query to count occurrences of distinct values −

mysql> select Value,count(*) from DemoTable group by Value;

This will produce the following output −

+-------+----------+
| Value | count(*) |
+-------+----------+
|    80 |        2 |
|    90 |        3 |
|   100 |        1 |
+-------+----------+
3 rows in set (0.00 sec)