MySQL in a Nutshell, 2nd Edition

Name

ATAN()

Synopsis

ATAN(number[, ...])

This function returns the arctangent, in radians, of a given number. To determine the arctangent of two numbers (Y and X), add the optional second argument to the function or use ATAN2(). The value of Y for a Cartesian plane is given as the first argument and X as the second. Here is an example:

SELECT ATAN(2);

+----------+
| ATAN(2)  |
+----------+
| 1.107149 |
+----------+