SQL MAX() and MIN()

• The MAX() function returns the maximum value of a column.
• The MIN() function returns the minimum value of a column.

1. SQL MAX() Function

Let's take an example.

SELECT MAX(age)
FROM Customers;

Here, the SQL command returns the largest value from the age column.

2. SQL MIN() Function

Let's take an example.

SELECT MIN(age)
FROM Customers;

Here, the SQL command returns the smallest value from the age column.

Aliases with MAX() and MIN()

In the above examples, the field name in the result set is MIN(age) and MAX(age).

It is also possible to give custom names to these fields using the AS keyword. For example,

SELECT MAX(age) AS max_age
FROM Customers;

Here, the field name MAX(age) is replaced with max_age in the result set.

MAX() and MIN() with Strings

The MAX() and MIN() functions also work with other data types such as text, not just numbers. For example,

SELECT MIN(first_name) AS min_first_name
FROM Customers;

Here, the SQL command selects the minimum value of first_name based on the dictionary order.

MAX() and MIN() in Nested SELECT

As we know, the MAX() function returns the minimum value. Similarly, the MIN() function returns the maximum value.

However, if we want to select the whole row containing that value, we can use the nested SELECT statement like this.

SELECT *
FROM Customers
WHERE age = (
    SELECT MIN(age)
    FROM Customers
);

Here, the SQL command selects all the customers with the smallest age.

-- returns 50 as highest
SELECT MAX(20, 30, 50) as highest;

-- returns 20 as lowest
SELECT MIN(20, 30, 50) as lowest;

SELECT *
FROM Customers
GROUP BY country
HAVING MAX(age);

Recommended Readings:

• SQL Alias
• SQL Subquery (Nested Select)