Page 275 - PYTHON-12

This command, on execution, shall return the minimum value from the specified column
(Salary) of the table Employee, which is 4500
• SUM()

SUM() function is used to find the total value of any column or expression based on a column. It
accepts the entire range of values as an argument, which is to be summed up on the basis of a
particular column, or an expression containing that column name. The SUM() function always
takes argument of integer type only. Sums of String and Date type data are not defined.

For example,
mysql> Select SUM(Salary) from EMPLOYEE;

Output:
+----------------+
| SUM(Salary) |
+----------------+

| 30700 |
+----------------+
This command, on execution, shall return the total of the salaries of all the employees from the
specified column (Salary) of the table Employee, which is 30700.
• AVG()

AVG() function is used to find the average value of any column or expression based on a column.
Like sum(), it also accepts the entire range of values of a particular column to be taken average
of, or even a valid expression based on this column name. Like SUM() function, the AVG()
function always takes argument of integer type only. Average of String and Date type data is not
defined.

For example,
mysql> Select AVG(Salary) from EMPLOYEE;

Output:
Ecode Name Salary Job City
+----------------+ E1 Ritu Jain NULL Manager Delhi
E2 Vikas Verma 4500 Executive Jaipur
| AVG(Salary) |
E3 Rajat Chaudhary 6000 Clerk Kanpur
+----------------+
E4 Leena Arora NULL Manager Bangalore
| 6140 |
E5 Shikha Sharma 8000 Accountant Kanpur
+----------------+
This command, on execution, shall return the average of the salaries of all the employees from
the specified column (Salary) of the table Employee, which is 6140.
Relational Database and SQL
• COUNT()

COUNT() function is used to count the number of values in a column. COUNT() takes one
argument, which can be any column name, or an expression based on a column, or an asterisk
(*). When the argument is a column name or an expression based on the column, COUNT()
returns the number of non-NULL values in that column. If the argument is asterisk (*), then
COUNT() counts the total number of records/rows satisfying the condition, if any, in the table.

12.45