MySQL ATAN2() Function

 The ATAN2() function in MySQL is used to return the arctangent (inverse tangent) of the two given numbers in radians. It is a more robust version of the standard ATAN() function because it takes both the x and y coordinates as arguments and can determine the correct quadrant of the angle.

Syntax:

ATAN2(y, x)

• y: The y-coordinate (numerator).
• x: The x-coordinate (denominator).

Description:

The ATAN2(y, x) function calculates the arctangent of the quotient of its arguments y/x, but also takes into account the sign of both arguments to determine the correct quadrant of the result. The result is in radians, and the angle is in the range -π to π (i.e., between -180° and 180°).

Example:

SELECT ATAN2(1, 1); -- Returns 0.7853981633974483, which is 45 degrees in radians

This example calculates the arctangent of 1/1, which results in an angle of 45 degrees (or π/4 radians).

Usage Example with Coordinates:

You can use ATAN2() to calculate the angle from the origin (0,0) to a point (x, y):

SELECT ATAN2(y, x) AS angle_in_radians
FROM points;

This query would compute the angle between the positive x-axis and the point (x, y) for each record in the points table.

Conversion to Degrees:

If you need the result in degrees instead of radians, you can use the DEGREES() function to convert it:

SELECT DEGREES(ATAN2(1, 1)); -- Returns 45, as it converts the result from radians to degrees

This returns the result of ATAN2(1, 1) in degrees, which is 45°.