Chapter 7, Problem 24P

Program Plan Intro

Aggregate Functions:

SQL has some built-in functions and they are called as aggregate functions. SQL contains five built-in functions. They are:

• SUM – This function is used to add values from the particular column.
  • Syntax: SELECT SUM(column_Name) FROM table_Name;
• COUNT – This is used to count the number of rows for the particular column.
  • Syntax: SELECT COUNT(column_Name) FROM table_Name;
• MAX – This function is used to get the maximum value from the column.
  • Syntax: SELECT MAX(column_Name) FROM table_Name;
• MIN – This function is used to get the minimum value from the column.
  • Syntax: SELECT MIN(column_Name) FROM table_Name;
• AVG – This function is used to get the average of all the values from the column.
  • Syntax: SELECT AVG(column_Name) FROM table_Name;

DISTINCT Keyword: “DISTINCT” keyword is used to avoid redundant data (removing duplicate values) from a column. The syntax for “DISTINCT” keyword is as follows:

Syntax:

SELECT DISTINCT column_Name FROM table_Name;

“NOT IN” Keyword: “NOT IN” keyword retrieve the elements of first table and the contents is not matched in second table.