How to calculate the arctangent value of a given value using the ATAN() function?

ATAN(X) is a MySQL built-in function that calculates the arctangent value of a given value. For example:

SELECT ATAN(0), ATAN(1), ATAN(2);
  -- +---------+--------------------+--------------------+
  -- | ATAN(0) | ATAN(1)            | ATAN(2)            |
  -- +---------+--------------------+--------------------+
  -- |       0 | 0.7853981633974483 | 1.1071487177940906 |
  -- +---------+--------------------+--------------------+

Reference information of the ATAN() function:

ATAN(Y, X): val
  Returns the arc tangent of Y, if X is not provided. It becomes a
  synonym for ATAN2(Y, X), if X is provided.

Arguments, return value and availability:
  Y: Required. The input value.
  X: Optional. If provided, ATAN(X, Y) is a synonym for ATAN2(Y, X).
  val: Return value. The arctangent value of the input value.
  Available since MySQL 4.0.

Related MySQL functions:

• TAN() - Tangent Trigonometric Value
• ATAN2() - 2-Argument Arctangent

⇒ ATAN2() - 2-Argument Arctangent

⇐ ASIN() - Arcsine Trigonometric Value

⇑ MySQL Functions on Numeric Values

⇑⇑ MySQL Function References