Group by and Having Clauses in SQL

Often used clauses with the aggregate functions.

SQL group by and having clauses

Through this article, we’ll learn what is Group by and Having clauses, when to use these clauses and how they are different than the where clause. The questions on these two clauses are mostly asked in the interviews that are focused on SQL.

What Does the Group by Clause Do?

The SQL GROUP BY clause is often used with the SELECT statement to group or arrange the rows together into multiple groups based on certain column(s) values. This GROUP BY clause follows the WHERE clause in a SELECT statement and precedes the ORDER BY clause.

The GROUP BY statement is often used with aggregate functions to group the result-set by one or more columns. These functions are:

• COUNT() : To count the number of records in a table.
• MAX() : To find the maximum value of a column.
• MIN() : To find the minimum value of a column.
• SUM() : To find the sum of values of a column.
• AVG() : To find the average of values of a column.

Note: we cannot use aggregate functions in WHERE clause.

The GROUP BY Syntax: