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Overview

The LEAST() function returns the least or smallest value in a list of values. It needs at least one argument to work with, and if you mix different types, like a text and a number, it will return an error. For example, comparing the greatest value among 4, “two”, and 9 would result in an error.

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Syntax

The syntax for the LEAST() function is as follows: 
LEAST(value_1, [value_n])
Where:
  • value_1: Represents the first value.
  • value_n: Represents one or more additional values, separated by commas.
Info:
-NULL values in the list will be ignored.
- The result will be NULL if all the expressions evaluate to NULL.

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Examples

Below are several examples of the LEAST() function:

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Case #1: Basic Usage

Consider the following example: 
SELECT LEAST(3,5,8,9,10);
The query will return 3, the smallest value among the provided values. 
 least 
-------
     3

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Case #2: String Comparison

String comparison is also supported, as shown below: 
SELECT LEAST('a','b','c','aa');
In this case, the result will be 'a', as it is the smallest string. 
 least 
-------
     a

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Case #3: Handling NULL Values

NULL values are ignored when determining the smallest value: 
SELECT LEAST (5,null,9);
The result will be the smallest non-NULL value, which is 5. 
 least 
-------
     5

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Case #4: Negative Numbers

Negative numbers can also be compared: 
SELECT LEAST (4,-4,-8,8);
This query will return -8, the smallest value among the provided numbers. 
 least 
-------
    -8

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Case #5: Using Table Data

Suppose we have a table named grades containing columns x, y, and z. 
CREATE TABLE grades (
    name TEXT,
    x INT,
    y INT,
    z INT
);

INSERT INTO grades (name, x, y, z)
VALUES
    ('Jane', 50, 0, 70),
    ('Rio', 60, 30, 80),
    ('John', 60, 60, 86),
    ('Rose', 80, 90, 88),
    ('Gary', 100, 80, 90);
To find the smallest value among these columns, you can use the following query: 
SELECT *, LEAST(x, y, z) AS least_grade FROM grades;
This query will add a new column named least_grade to the result, displaying the smallest value among columns x, y, and z. 
 name |  x  | y  | z  | least_grade 
------+-----+----+----+-------------
 Jane |  50 |  0 | 70 |           0
 Rio  |  60 | 30 | 80 |          30
 John |  60 | 60 | 86 |          60
 Rose |  80 | 90 | 88 |          80
 Gary | 100 | 80 | 90 |          80