Chapter 7, Problem 53P

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;

“ORDER BY” Clause:

SQL contains “ORDER BY” clause in order to sort rows. The values get sorted in ascending and descending order. The keyword used to sort values in ascending order is “ASC” and for descending order is “DESC”. By default, it sorts values by ascending order.

Syntax:

SELECT column_Name1, column_Name2 FROM table_Name ORDER BY column_Name2;

Join:

Join is a relational operation, which combines the data from two or more tablesinto 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.

“UNION” operator:

The UNION set operator is used to combine the output of two or more than two queries and produce a result. The produced result contains unique values.

Syntax: QUERY UNION QUERY;

“NOT IN” operator:

The “NOT IN” operator used to select not matching rows from appropriate tables.

Syntax: SELECT column_name1, column_name2, column_nameN FROM table_name WHERE column_name1 NOT IN column_name2;