ATAN2()
ATAN2(number,number)
This function returns the arctangent, in radians, of X and Y for a point on a Cartesian plane. The value for Y is given as the first argument and X as the second. The reverse function is TAN(). Here is an example:
SELECT ATAN2(10, 5); +--------------+ | ATAN2(10, 5) | +--------------+ | 1.107149 | +--------------+