Can DISTINCT and COUNT be used together in MySQL queries?

We can use DISTINCT and COUNT together in a MySQL query. First, let's create a table. The CREATE command is used to create a table.

mysql> create table DistCountDemo
　　　-　> (
　　　-　> id int,
　　　-　> name varchar(100),
　　　-　> age int
　　　-　> );

Insert records with the help of the INSERT command.

mysql> insert into DistCountDemo values(1,'John',23);
mysql> insert into DistCountDemo values(2,'Bob',24);
mysql> insert into DistCountDemo values(3,'John',23);
mysql> insert into DistCountDemo values(4,'Carol',23);

Display all records with the help of the SELECT statement.

mysql> select　*FROM DistCountDemo;

The following is the output.

+------+-------+------+
| id | name | age |
+------+-------+------+
|　　　　1　| John |　　　23　|
|　　　　2　| Bob |　　　24　|
|　　　　3　| John |　　　23　|
|　　　　4　| Carol |　　　23　|
+------+-------+------+
4　rows in set (0.00 sec)

Use COUNT and DISTINCT to find23number of students of that age.

mysql> SELECT COUNT(DISTINCT name) FROM DistCountDemo WHERE age=23;

The following is the output.

+----------------------+
| COUNT(DISTINCT name) |
+----------------------+
|　　　　　　　　　　　　　　　　　　　　2　|
+----------------------+
1　row in set (0.05　sec)