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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:

Name Description
ALL Applies to all values.
DISTINCT Consider each unique value. DISTINCT is not meaningful with MAX function.
expression Expression made up of a single constant, variable, scalar function, or column name or any combination of arithmetic, bitwise, and string operators. MAX can be used with numeric, character, and datetime columns, but not with bit columns. Aggregate functions and subqueries are not permitted.

DBMS Support: COUNT() function

DBMS Command
MySQL Supported
PostgreSQL Supported
SQL Server Supported
Oracle Supported

Syntax diagram - MAX() 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 Expression: MAX() function.

Relational Algebra Tree:

Relational Algebra Tree: MAX() function.

Output:

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

Pictorial Presentation:

SQL MAX() function example

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 Expression: SQL MAX() with addition of two columns.

Relational Algebra Tree:

Relational Algebra Tree: SQL MAX() with addition of two columns.

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.

Check out our 1000+ SQL Exercises with solution and explanation to improve your skills.

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