Chapter 8, Problem 62P

Program Plan Intro

SELECT statement:

It is used to retrieve information from the table or database. The syntax for the “SELECT” statement is given below:

Syntax:

SELECT * FROM table_Name;

“Round()” function:

This function is used to round a number that specified in decimal places. The format of the “Round()” function is as follows:

Syntax:

ROUND(number, decimal_places)

AVG function:

• • It is one of the function of aggregate function.
• • This function is used to get the average of all the values from the column.
• • Syntax: SELECT AVG(column_Name) FROM table_Name;

COUNT function:

• • It is one function of the aggregate function.
• • This is used to count the number of rows for the particular column.
• • Syntax: SELECT COUNT(column_Name) FROM table_Name;

“GROUP BY” Clause:

The GROUP BY clause is used to group the result of a SELECT statement done on a table where the tuple values are similar for more than one column.

Syntax:

SELECT expression1, expression2, expression_n, aggregate_function (expression)FROM table_name WHERE conditions GROUP BY expression1, expression2, expression_n;

ORDER BY Clause:

SQL contains “ORDER BY” clause in order to sort rows. The values get sorted in ascending as well as 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;

“HAVING” Clause:

The “HAVING” clause is used to restrict the groups that are included.

• • This restriction does not apply to individual rows but relatively apply to groups.

Example:

The example for “HAVING” clause is given below:

SELECT STUDENT_ID, NAME, AGE, ADDRESS, TOTAL_MARK FROM STUDENTS GROUP BY AGE HAVING COUNT(AGE) >= 10;

• • The above query is used to display a record for a similar age count that would be more than or equal to “10”.