SQL: MIN Function

This SQL tutorial explains how to use the SQL MIN function with syntax and examples.

Description

The SQL MIN function is used to return the minimum value of an expression in a SELECT statement.

Syntax

The syntax for the MIN function in SQL is:

SELECT MIN(aggregate_expression)
FROM tables
[WHERE conditions];

OR the syntax for the MIN function when grouping the results by one or more columns is:

SELECT expression1, expression2, ... expression_n,
       MIN(aggregate_expression)
FROM tables
[WHERE conditions]
GROUP BY expression1, expression2, ... expression_n;

Parameters or Arguments

expression1, expression2, ... expression_n

Expressions that are not encapsulated within the MIN function and must be included in the GROUP BY clause at the end of the SQL statement.

aggregate_expression

This is the column or expression from which the minimum value will be returned.

tables

The tables that you wish to retrieve records from. There must be at least one table listed in the FROM clause.

WHERE conditions

Optional. These are conditions that must be met for the records to be selected.

Example - With Single Expression

The simplest way to use the SQL MIN function would be to return a single field that calculates the MIN value.

For example, you might wish to know the minimum salary of all employees.

SELECT MIN(salary) AS "Lowest salary"
FROM employees;

In this SQL MIN function example, we've aliased the MIN(salary) field as "Lowest salary". As a result, "Lowest salary" will display as the field name when the result set is returned.

Example - Using SQL GROUP BY

In some cases, you will be required to use the SQL GROUP BY clause with the SQL MIN function.

For example, you could also use the SQL MIN function to return the name of each department and the minimum salary in the department.

SELECT department, MIN(salary) AS "Lowest salary"
FROM employees
GROUP BY department;

Because you have listed one column in your SQL SELECT statement that is not encapsulated in the SQL MIN function, you must use the SQL GROUP BY clause. The department field must, therefore, be listed in the GROUP BY section.