REGR_COUNT

Description

Returns the number of non-null (y, x) pairs in a group, where x is the independent variable and y is the dependent variable. If there are no valid non-null pairs, the function returns 0.

Syntax

REGR_COUNT(<y>, <x>)

Parameters

Parameter	Description
<y>	The dependent variable. Supported type: Double.
<x>	The independent variable. Supported type: Double.

Return Value

Returns a BIGINT value representing the number of non-null (y, x) pairs. If there are no rows in the group, or there are no valid non-null (y, x) pairs, the function returns 0.

Example

CREATE TABLE test_regr (
  `id` int,
  `x` double,
  `y` double
) DUPLICATE KEY (`id`)
DISTRIBUTED BY HASH(`id`) BUCKETS AUTO
PROPERTIES (
  "replication_allocation" = "tag.location.default: 1"
);

INSERT INTO test_regr VALUES
(1, 0, NULL),
(2, 1, 3),
(2, 2, 5),
(2, 3, 7),
(2, 4, 9),
(2, 5, NULL);

SELECT id, REGR_COUNT(y, x) FROM test_regr GROUP BY id ORDER BY id;

+------+-------------------+
| id   | REGR_COUNT(y, x)  |
+------+-------------------+
|    1 |                 0 |
|    2 |                 4 |
+------+-------------------+

REGR_COUNT counts only non-null (y, x) pairs, so group 1 returns 0.