MIN_N, MAX_N

Returns the n smallest or largest values from an expression as an array.

These functions are supported from v4.0.

Syntax

MIN_N(<expr>, <n>)
MAX_N(<expr>, <n>)

Parameters

• expr: An expression of any sortable type (STRING, BOOLEAN, DATE, DATETIME, or numeric type).
• n: An INTEGER literal greater than 0. The maximum value is 10000.

Return value

• MIN_N: Returns an ARRAY containing the n smallest values from the expression, sorted in ascending order.
• MAX_N: Returns an ARRAY containing the n largest values from the expression, sorted in ascending order.

The array elements have the same type as the input expression.

• If the number of distinct values is less than n, returns all values.
• NULL values are ignored.
• If all values are NULL, returns an empty array.

Examples

Basic usage with MIN_N and MAX_N

1. Create a table scores.

   CREATE TABLE scores (
       student_id INT,
       subject STRING,
       score INT
   ) DISTRIBUTED BY HASH(`student_id`);

2. Insert values into this table.

   INSERT INTO scores VALUES
   (1, 'math', 85),
   (2, 'math', 92),
   (3, 'math', 78),
   (4, 'math', 95),
   (5, 'math', 88),
   (6, 'math', 82),
   (7, 'math', 90),
   (8, 'math', 87),
   (9, 'math', 93),
   (10, 'math', 89);

3. Get the 3 smallest and 3 largest scores.

   SELECT 
       MIN_N(score, 3) AS min_3_scores,
       MAX_N(score, 3) AS max_3_scores 
   FROM scores;
   +----------------+----------------+
   | min_3_scores   | max_3_scores   |
   +----------------+----------------+
   | [85,82,78]     | [90,92,95]     |
   +----------------+----------------+

4. Get the smallest and largest scores by subject.

   SELECT 
       subject, 
       MIN_N(score, 2) AS min_2_scores,
       MAX_N(score, 2) AS max_2_scores 
   FROM scores 
   GROUP BY subject;
   +---------+---------------+---------------+
   | subject | min_2_scores  | max_2_scores  |
   +---------+---------------+---------------+
   | math    | [82,78]       | [92,95]       |
   +---------+---------------+---------------+

Using with string values

CREATE TABLE products (
    id INT,
    name STRING,
    price DECIMAL(10,2)
) DISTRIBUTED BY HASH(`id`);

INSERT INTO products VALUES
(1, 'apple', 2.50),
(2, 'banana', 1.80),
(3, 'cherry', 4.20),
(4, 'date', 3.10),
(5, 'elderberry', 5.50);

SELECT 
    MIN_N(name, 3) AS min_3_names,
    MAX_N(name, 3) AS max_3_names 
FROM products;
+---------------------------+--------------------------+
| min_3_names               | max_3_names              |
+---------------------------+--------------------------+
| [cherry,banana,apple]     | [cherry,date,elderberry] |
+---------------------------+--------------------------+

Edge case: n larger than number of values

SELECT 
    MIN_N(score, 15) AS all_scores_min,
    MAX_N(score, 15) AS all_scores_max 
FROM scores;
+----------------------------------+----------------------------------+
| all_scores_min                   | all_scores_max                   |
+----------------------------------+----------------------------------+
| [95,93,92,90,89,88,87,85,82,78]  | [78,82,85,87,88,89,90,92,93,95]  |
+----------------------------------+----------------------------------+

Using with date values

CREATE TABLE events (
    id INT,
    event_name STRING,
    event_date DATE
) DISTRIBUTED BY HASH(`id`);

INSERT INTO events VALUES
(1, 'conference', '2024-03-15'),
(2, 'workshop', '2024-01-20'),
(3, 'seminar', '2024-05-10'),
(4, 'meeting', '2024-02-28'),
(5, 'training', '2024-04-05');

SELECT 
    MIN_N(event_date, 3) AS earliest_3_dates,
    MAX_N(event_date, 3) AS latest_3_dates 
FROM events;
+------------------------------------+------------------------------------+
| earliest_3_dates                   | latest_3_dates                     |
+------------------------------------+------------------------------------+
| [2024-03-15,2024-02-28,2024-01-20] | [2024-03-15,2024-04-05,2024-05-10] |
+------------------------------------+------------------------------------+

keyword

MIN_N, MAX_N