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ATAN2()

Returns the arctangent of Y / X in radians. Unlike ATAN(Y/X), ATAN2(Y, X) uses the signs of both arguments to determine the correct quadrant of the result.

Description

The ATAN2() function returns the angle (in radians) between the positive x-axis and the point (X, Y). Both X and Y can be any numeric type. The result is in the range [-PI, PI].

Syntax

> ATAN2(Y, X)

Arguments

Arguments Description
Y Required. The y-coordinate.
X Required. The x-coordinate.

Examples

DROP DATABASE IF EXISTS atan2_tests;
CREATE DATABASE atan2_tests;
USE atan2_tests;

SELECT ATAN2(1, 1) AS quadrant1;
SELECT ATAN2(1, -1) AS quadrant2;
SELECT ATAN2(-1, -1) AS quadrant3;
SELECT ATAN2(-1, 1) AS quadrant4;
SELECT ATAN2(0, -1) AS pi_result;
SELECT ATAN2(NULL, 1) AS null_y;
SELECT ATAN2(1, NULL) AS null_x;

DROP DATABASE atan2_tests;