Multiple Row Function – Group Function in SQL

Multiple Row Function :

• Multiple row function is also called as group function or it is also called as aggregate function.
• group function operate on set of rows to give one result per group

Types of Group Function :

1. AVG  – average value of number of rows in a table, it ignoring null value
2. COUNT  – number of rows( count all selected rows using * , including duplicates and rows with null value )
3. MAX  – maximum value of expression, ignore null values
4. MIN   – minimum value of expression, ignore null values
5. SUM – sum of  values of number of rows in a table, it ignore null values

Example : 

Question : Display the total salary in employee table

Query : SELECT SUM( sal ) as total FROM emp;

Question : Display Average salary in employee table

Query : SELECT AVG( sal ) as average FROM emp;

Question : Display Min and Max salary in employee table

Query : SELECT MIN( sal ) as minsal MAX( sal ) as maxsal FROM emp;

Question : Display  total count of rows  in employee table

Query : SELECT COUNT( * ) as average FROM emp;