How to count the distinct column in MySQL?
You need to use GROUP BY for this. Let us first create a table −
mysql> create table DemoTable
(
StudentFirstName varchar(20)
);
Query OK, 0 rows affected (0.74 sec)
Insert records in the table using insert command −
mysql> insert into DemoTable values('John');
Query OK, 1 row affected (1.34 sec)
mysql> insert into DemoTable values('Carol');
Query OK, 1 row affected (0.28 sec)
mysql> insert into DemoTable values('John');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('John');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('Bob');
Query OK, 1 row affected (0.25 sec)
mysql> insert into DemoTable values('David');
Query OK, 1 row affected (0.55 sec)
mysql> insert into DemoTable values('Bob');
Query OK, 1 row affected (0.08 sec)
mysql> insert into DemoTable values('Carol');
Query OK, 1 row affected (0.37 sec)
mysql> insert into DemoTable values('Robert');
Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −
mysql> select * from DemoTable;
This will produce the following output −
+------------------+
| StudentFirstName |
+------------------+
| John |
| Carol |
| John |
| John |
| Bob |
| David |
| Bob |
| Carol |
| Robert |
+------------------+
9 rows in set (0.00 sec)
Here is the query to count the distinct column in MySQL −
mysql> select StudentFirstName,count(*) from DemoTable
group by StudentFirstName;
This will produce the following output −
+------------------+----------+
| StudentFirstName | count(*) |
+------------------+----------+
| John | 3 |
| Carol | 2 |
| Bob | 2 |
| David | 1 |
| Robert | 1 |
+------------------+----------+
5 rows in set (0.00 sec)
Published on 03-May-2019 13:15:11
