Group By in SQL With Example [ COUNT, AVG, MAX, MIN ,SUM ] Video

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Group By in SQL With Example [ COUNT, AVG, MAX, MIN ,SUM ] Video

Learning Group By in SQL is a little bit tricky for a newbie programmer. In today’s lesson, I will give in-depth discussion about Group By in SQL with Example using Aggregate functions.

Few Questions and Answers in learning SQL Group By Functions

What is Group By in SQL?

Group functions in sql are mathematical functions to operate on sets of rows to give one result per set. ex: “Find the number of employee in each Department”.

What Group By Does in SQL?

It arrange identical data into groups with the help of some aggregate functions.

What is Aggregate Functions in SQL?

is a function where the values of multiple rows are grouped together to form a single summary value.

Where Group By Having in SQL?

The HAVING clause is used to specify which groups are to be displayed, and thus, you further restrict the groups on the basis of aggregate information.

Lesson Objectives

Here’s the main objectives after completing this lesson, you will be able to do the following:

  • Identify the available Group Functions
  • Describe the use of group functions
  • Aggregate data using GROUP BY clause
  • Include or Exclude grouped rows by using the HAVING clause

Types of group functions

The GROUP BY statement is often used with aggregate functions (AVG, COUNT, MAX, MIN, and SUM) to group the result-set by one or more columns.

Group by in SQL Aggregate Function

  • COUNT

    Calculate the number of rows in a set

  • AVG

    Calculates the average of the specified columns in a set of rows.

  • MAX

    Returns the largest value of the selected column.

  • MIN

    Returns the smallest value of the selected column.

  • SUM

    Returns the total sum of a numeric column.

Group Functions Syntax

Sample table used in this lesson

EMP_IDEMPNAMECONTACTSALARYDEPT_NAME
1Kobe Bryant789541250000.00SHIPPING
2Jordan Michael789541270000.00IT
3James BOnd123245645000.00SALES
4Anne Curtis787889835000.00SHIPPING
5John Wick1233455765000.00EXECUTIVE
6Hatch Glets6654878257000.00IT
7Xyre Anderson7877892348000.00SALES
TABLE NAME: tblsampleemployee

Watch the Video demonstration here:

Count with group by statement

The following SQL statement finds the number of Employee by Department:

SQL Group by Count Statement

Results of Count with group by Statement

DEPT_NAMENo of Employee
EXECUTIVE1
IT2
SALES2
SHIPPING2

SQL Group by using AVG

The following SQL statement finds the average SALARY of all Employee:

SQL statement using AVG

RESULT

Average Salary
52857.142857

AVG with Group By in SQL Example

The following SQL statement finds the average SALARY of all Employee by Department:

Another SQL statement using AVG

SQL group by Example Results

DEPT_NAMEAverage Salary
EXECUTIVE65000.000000
IT63500.000000
SALES46500.000000
SHIPPING42500.000000

Query using MAX AND MIN With group by statement

The following SQL statement finds the Maximum and Minimum Salary by Department:

Group by in SQL Statement

Results of Using MAX and MIN

DEPT_NAMEMaximum SalaryMinimum Salary
EXECUTIVE65000.0065000.00
IT70000.0057000.00
SALES48000.0045000.00
SHIPPING50000.0035000.00

Query using SUM With Group by statement

The following SQL statement finds the Payroll by Department:

Group by statement using SUM

Results

DEPT_NAMEPAYROLL
EXECUTIVE65000.00
IT127000.00
SALES93000.00
SHIPPING85000.00

Excluding group results: The having clause

Use the HAVING clause to restrict groups:

  1. Rows are grouped.
  2. The group function is applied.
  3. Groups matching the Having clause are displayed.

Syntax of Group by HAVING in SQL

Example: The following SQL statement finds the Total Payroll exceeding 80,000.00 by Department.

SQL Statement Using Having Clause

Results of using Having Clause

DEPT_NAMEPAYROLL
IT127000.00
SALES93000.00
SHIPPING85000.00

Based on the example of using HAVING Clause, it displays the DEPT_NAME and PAYROLL that exceeds 80000. You will also notice that the EXECUTIVE department has been excluded and the list is sorted by Department Name.

NOTE: You can use the HAVING clause to specify which groups are to be displayed, and thus, you further restrict the groups on the basis of aggregate information.

Summary

In this lesson, you should have learned how to:

  • Use the functions AVG, COUNT, MAX, MIN, SUM
  • Write queries that use the Group By clause
  • Write queries that use the Having Clause

Related Article

Inquiries

I hope that you have learned something new today. If you have any questions or suggestions about the Group by in SQL with examples, please feel free to leave a comment below.

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