SQL Server ACOS() Function

Summary: in this tutorial, you will learn how to use the SQL Server ACOS() function to return the arccosine of a number.

Introduction to the SQL Server ACOS() function

The arccosine function is the inverse function of the cosine function. The arccosine returns the angle of a cosine in radians.

In SQL Server, you can use the ACOS() function that returns an angle (in radians) of a specified cosine.

Here’s the syntax of the ACOS() function:

ACOS(n)Code language: SQL (Structured Query Language) (sql)

In this syntax:

n is a float value you want to calculate the arccosine. The valid range of n is from -1 to 1.

The ACOS() function returns an angle (in radians) whose cosine equals the n. If n is invalid, the ACOS() function will raise an error. If n is NULL, the ACOS() function will return NULL.

SQL Server ACOS() function examples

Let’s take some examples of using the SQL Server ACOS() function.

1) Basic SQL Server ACOS() function example

The following example uses the ACOS() function to return the arccosine of -1:

SELECT ACOS(-1) angle;Code language: SQL (Structured Query Language) (sql)

Output:

angle
-----------------
3.141592653589793Code language: SQL (Structured Query Language) (sql)

It returns the PI value.

2) Using ACOS() function with variables

The following example uses the ACOS() function with variables:

DECLARE @value FLOAT;
SET @value = 1;

SELECT ACOS(@value) AS arccosine_value;Code language: SQL (Structured Query Language) (sql)

Output:

arccosine_value
---------------
0Code language: SQL (Structured Query Language) (sql)

In this example, we set the @value to 1 and then use the ACOS() function to calculate the arccosine of 1, which is zero radians.

Summary

Use the ACOS() function to return the arccosine of a number.

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