SQL MAX() function

MAX() function

The aggregate function SQL MAX() is used to find the maximum value or highest value of a certain column or expression. This function is useful to determine the largest of all selected values of a column.

Syntax:

MAX ([ALL | DISTINCT] expression ) 

DB2 and Oracle Syntax:

MAX ([ALL | DISTINCT] expression ) OVER (window_clause) 

Parameters:

DBMS Support: COUNT() function

Syntax diagram - MAX() function

Example:

To get maximum 'ord_amout' from the 'orders' table, the following SQL statement can be used :

Sample table: orders

SELECT MAX (ord_amount)
FROM orders;

Relational Algebra Expression:

Relational Algebra Tree:

Output:

MAX(ORD_AMOUNT)
---------------
           4500

Pictorial Presentation:

SQL MAX() with addition of two columns

To get the maximum value of (opening_amt+receive_amt) from the customer table, the following SQL statement can be used :

Sample table: customer

SELECT MAX (opening_amt+receive_amt) 
FROM customer;

Relational Algebra Expression:

Relational Algebra Tree:

Output:

MAX(OPENING_AMT+RECEIVE_AMT)
----------------------------
                       19000

Note: Outputs of the said SQL statement shown here is taken by using Oracle Database 10g Express Edition

Here is a slide presentation of all aggregate functions.

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