>>-ATAN--(--expression--)--------------------------------------><
The schema is SYSFUN.
Returns the arctangent of the argument as an angle expressed in radians.
The argument can be of any built-in numeric data type. It is converted to a &dpfpn; for processing by the function.
The result of the function is a double-precision floating-point number. The result can be null; if the argument is null, the result is the null value.