Syntax:
ATAN(Y,X), ATAN2(Y,X)

Returns the arc tangent of the two variables X and Y. It is similar to
calculating the arc tangent of Y / X, except that the signs of both
arguments are used to determine the quadrant of the result. Returns
NULL if X or Y is NULL.

URL: https://dev.mysql.com/doc/refman/8.0/en/mathematical-functions.html

