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ACOS

The ACOS function is used to calculate the arccosine (inverse cosine) of a number. It takes a single numeric argument, which should be a float value in the range of -1 to 1, and returns the arccosine of that number in radians.

Syntax​

ACOS(value)
  • value: A numeric expression for which the arccosine is to be calculated. The value should be in the range of -1 to 1.

Examples​

Let's consider a table named SingleItem with the following schema:

CREATE TABLE SingleItem (id INTEGER);

Insert a row into the SingleItem table:

INSERT INTO SingleItem VALUES (0);

Example 1: Using ACOS with float values​

SELECT ACOS(0.5) AS acos1, ACOS(1) AS acos2 FROM SingleItem;

Result:

     acos1      |     acos2
----------------+---------------
 1.0471975511966 | 0.0

Example 2: Using ACOS with NULL values​

SELECT ACOS(NULL) AS acos FROM SingleItem;

Result:

  acos
-------
 (null)

Errors​

The ACOS function requires a numeric value in the range of -1 to 1 as its argument. Using non-numeric values or more than one argument will result in an error.

Example 3: Using ACOS with non-numeric values​

SELECT ACOS('string') AS acos FROM SingleItem;

Error: Function requires a numeric value.

Example 4: Using ACOS with multiple arguments​

SELECT ACOS(1.0, 2.0) AS acos FROM SingleItem;

Error: Function expects 1 argument, but 2 were provided.