Chapter 3, Problem 3.31RQ

Program Plan Intro

SQL:

• SQL stands for “Structured Query Language”.
• The current version of SQL is “ANSI SQL – 92”.
• It contains constructs which are used to define and process database. They are executed using DBMS-supplied command prompt.
• SQL is not a programming language. It is text-based and it is also called as data sublanguage. In order to get SQL as a complete programming language, it should be included in scripting languages like Java, C#, and so on.

Display values from table:

The contents from the table can be viewed by using “SELECT” statement which comes under Data Manipulation Language (DML). Syntax to view the contents using asterisk (*) is as follows:

SELECT * FROM table_Name;

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;