Five Important aggregate functions are SUM, AVG, MIN, MAX and COUNT. They are called aggregate functions because they summarize the results of a query, rather than listing all of the rows.
- SUM () gives the total of all the rows, satisfying any conditions, of the given column, where the given column is numeric.
- AVG () gives the average of the given column.
- MIN () gives the smallest figure in the given column.
- MAX () gives the largest figure in the given column.
- COUNT () gives the number of rows satisfying the conditions
1. SUM( )
The SUM function returns the total sum of a column. NULL values are not included in the calculation.
Syntax:
SELECT SUM (column) FROM table
For example:
SELECT SUM (RollNumber) FROM Student;
2. AVG( )
The AVG function returns the average value of a column in a selection. NULL values are not included in the calculation.
Syntax :
SELECT AVG (column) FROM table
For example:
SELECT AVG(RollNumber) FROM Student;
3. MIN( )
The MIN function returns the lowest value in a column. NULL values are not included in the calculation.
Syntax :
SELECT MIN(column) FROM table;
For example:
SELECT MIN(RollNumber) FROM Student;
4. MAX( )
The MAX function returns the highest value in a column. NULL values are not included in the calculation.
Syntax :
SELECT MAX(column) FROM table;
For example:
SELECT MAX(RollNumber) FROM Student;
5. COUNT( )
The keyword COUNT can be used together to count the number of distinct results.
Syntax :
SELECT COUNT (column) FROM table;
For example:
SELECT COUNT (RollNumber) FROM Student;