SQL Server ATN2() Function
The ATN2() function in SQL Server calculates the arctangent (inverse tangent) of two numbers. The arctangent is the angle whose tangent is the ratio of the two input numbers. The result is an angle, expressed in radians.
ATN2(): Definition and Usage
ATN2() is particularly useful when working with Cartesian coordinates (x, y) to determine the angle between the positive x-axis and the line segment from the origin (0,0) to the point (x, y). The function considers the signs of both inputs to determine the correct quadrant for the angle. The returned angle is in radians.
Syntax
Syntax
ATN2(a, b)
Parameter Values
| Parameter | Description |
|---|---|
a |
The y-coordinate (a numeric value). This is required. |
b |
The x-coordinate (a numeric value). This is required. |
Examples
Calculating the Arctangent of Two Values
This example calculates the arctangent of 0.5 (0.5 / 1).
Syntax
SELECT ATN2(0.50, 1);
Output
0.463647609000806
Calculating the Arctangent of Different Values
This example calculates the arctangent of -0.4 (-0.8 / 2).
Syntax
SELECT ATN2(-0.8, 2);
Output
-0.38050637711219