SQL - Aggregate Functions

What are Aggregate Functions? 


Aggregate Functions work on the calculation on a set of values and return a single value. we often use aggregate functions with the GROUP BY and HAVING CLAUSE of the SELECT statement.

The following Various Aggregate Functions:-
  • AVG
  • COUNT
  • MIN
  • MAX
  • SUM

AVG

The AVG() function is used to return the average value of n.

Syntax:-
SELECT  AVG (column_name)
FROM table_name
WHERE conditions;
Example: Let's see how to use AVG function in the table.

Query :

SELECT  AVG (Salary) FROM customers;
Output :

Now, you can see AVG() Function calculated average salary in the salary column.


COUNT


The  COUNT() function is used to returns the number of rows.

Syntax:-
SELECT  COUNT (column_name)
FROM table_name
WHERE conditions;
Example: Let's see how to use the COUNT function in the table.

Query:

SELECT  COUNT (Salary)
FROM customers
WHERE Customer_Id = 4;
Output :

Now, you can see COUNT() Function calculated number of row in the salary column.


MIN


The  MIN() function is used to returns the minimum value.

Syntax:-

SELECT  MIN (column_name)
FROM table_name
WHERE conditions;
Example: Let's see how to use MIN function in the table.

Query :

SELECT  MIN (Salary)
FROM customers;
Output :

Now, you can see MIN() Function calculated minimum salary in the salary column.


MAX


The  MAX() function is used to returns the maximum value.

Syntax:-

SELECT  MAX (column_name)
FROM table_name
WHERE conditions;
Example: Let's see how to use the MAX function in the table.

Query :

SELECT  MAX (Salary)
FROM customers;
Output :

Now, you can see MAX() Function calculated maximum salary in the salary column.



SUM


The  SUM() function is used to returns the sum of the column.

Syntax:-

SELECT  SUM (column_name)
FROM table_name
WHERE conditions;
Example: Let's see how to use the SUM() function in the table.

Query :

SELECT  SUM (Salary)
FROM customers
WHERE Customer_Id = 5;
Output :

Now, you can see SUM() Function calculated the sum of the column in the salary column.



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