Aggregate functions perform a calculation on a set of column values and return a single value.
We will use the student to show how to use SQL aggregate functions:
| Studentid |
Name |
Course |
City |
Marks |
| 201 |
Nikita |
BCA |
Delhi |
66 |
| 204 |
Sindhu |
BE |
Mysore |
74 |
| 208 |
Sanvi |
BE |
Mysore |
69 |
| 212 |
Sam |
M.tech |
Bangalore |
65 |
| 220 |
Karthik |
MCA |
Mysore |
70 |
The aggregate functions name are as follows:
- COUNT() - Returns the number of rows
Select count(*) from student.
The result of this will be the number 5.
- AVG() - Returns the average value
Select avg(marks) from student.
The result of this will be the number 68.8.
- MAX() - Returns the maximum value in column
Select max(marks) from student.
The result of this will be the number 74.
- MIN() - Returns the smallest value in column
Select min(marks) from student.
The result of this will be the number 65.
- SUM() - Returns the sum value of a column.
Select sum(marks) from student.
The result of this will be the number 344.
