How to count the number of occurrences of a specific value in a column with a single MySQL query?

For this, you can use GROUP BY clause along with IN(). Let us first create a table −

mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(100)    -> ); Query OK, 0 rows affected (0.87 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable(Name) values('John'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable(Name) values('Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Name) values('David'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable(Name) values('Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Name) values('Chris'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable(Name) values('John'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(Name) values('Carol'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Name) values('Sam'); Query OK, 1 row affected (0.19 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+----+-------+ | Id | Name | +----+-------+ | 1 | John | | 2 | Chris | | 3 | David | | 4 | Chris | | 5 | Chris | | 6 | John | | 7 | Carol | | 8 | Sam | +----+-------+ 8 rows in set (0.00 sec)

Now, count the number of occurrences of a specific value in a column with a single query −

mysql> select Name,count(*) AS Occurrences from DemoTable -> where Name in('John','Chris') group by Name;

This will produce the following output −

+-------+-------------+ | Name | Occurrences | +-------+-------------+ | John | 2 | | Chris | 3 | +-------+-------------+ 2 rows in set (0.00 sec)