Using the Group Functions

What Are Group Functions ?

• Group functions operate on sets of rows to give one result per group.

Types of Group Functions :

• AVG
• COUNT
• MAX
• MIN
• SUM

Group Functions : Syntax

• SELECT [column,] group_function(column), ... FROM table [WHERE condition] [GROUP BY column] [ORDER BY column];

Nesting Functions

SELECT ename, UPPER(SUBSTR (ENAME, 1, 8) || '_US') FROM emp WHERE deptno = 10;
The slide example displays the last names of employees in department 10.

The evaluation of the SQL statement involves three steps:

• – The inner function retrieves the first eight characters of the last name.

• Result1 = SUBSTR (ENAME, 1, 8)
• – The outer function concatenates the result with _US.

• Result2 = Result1 || '_US'
• – The outermost function converts the results to uppercase.