Chapter 7, Problem 55P

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;

Join:

Join is a relational operation, which combines the data from two or more tables into single table or view, then that is called as Join.

Inner join:

The “inner join” keyword is to select the matching records from two tables. The syntax of “inner join” is as follows:

Syntax:

SELECT column_name FROM table1 INNER JOIN table2 ON table1.column_name=table2.column_name;

“AND” operator:

The operator used to check two or more conditions using single query. The “AND” operator returns “true” when two conditions are satisfied in the query.