In this table, to find the average salary for each department’s employees, we’ll use the following query.Let’s take a sample “Employee_dept” table: Let’s apply the concepts stated above to the columns of a table to get an even clearer picture of the Group By statement. We have used the AVG() aggregate function for this purpose. Let’s see what happens when we use the ORDER BY clause.There was no ORDER BY clause, so the table has no definite order of rows. To find the maximum salary for each department with “Dept_ID” greater than 1003: The WHERE clause can also be used in the query, and it precedes the GROUP BY statement.To find the number of employees from each city, this is what is required:Īnd it will result in the following table:Īs we can see, the groups have been ordered in ascending order, according to the number of employees from each city. Let’s see what happens when we use an aggregate function without the GROUP BY statement.The above query will result in the following: The WHERE clause will be applied to the rows before they are grouped.
To find the total salary of all the employees:Īs we can see, the count function on “Dept_ID” returns the total number of records in the table, and the sum function on “Salary” returns the arithmetic sum of all the employees’ salaries.
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