The atan() function returns the inverse tangent (arctangent) of a specified argument, expressed in radians. See also atand() to return the result in degrees, and atan2() to calculate the arctangent of a ratio of two arguments.
Syntax
ATAN(x)
Arguments
x: A number of type real or double precision.
Return type
Same as the input type (real or double precision).
Examples
Basic usage
SELECT ATAN(1);
atan
--------------------
0.7853981633974483
(1 row)