MySQL Count
This example illustrates how to use count() in MySQL database.
Count(): The Count() is an aggregate function that counts all the rows in a specified table. It returns a numeric value. If you use COUNT(*) that counts the number of rows.
Table: employee
CREATE TABLE `employee` ( `emp_id` int(11) NOT NULL auto_increment, `emp_name` varchar(10) character set utf8 NOT NULL, `emp_salary` int(11) NOT NULL, `emp_startDate` datetime NOT NULL, `dep_name` varchar(50) NOT NULL, PRIMARY KEY (`emp_id`) ) |
To select all records use the query:
SELECT * FROM employee; |
Output:
To use COUNT(*) with the sql query:
SELECT COUNT(*) FROM employee; |
Output:
To use COUNT(column_name) with the GROUP BY sql query:
You can use count function on column. If it is used with group by clause then it counts all the items that are in a group. For example, the query below shows the department name and total no of employee in the department with the help of count function.
SELECT dep_name,COUNT(emp_name) As Total FROM employee GROUP BY (dep_name); |