In MariaDB, COS() is a built-in numeric function that returns the cosine of its argument, where the argument is provided in radians.

Syntax

The syntax goes like this:

COS(X)

Where X is the number, provided in radians.

Example

Here’s an example:

SELECT COS(3);

Result:

+---------------------+
| COS(3)              |
+---------------------+
| -0.9899924966004454 |
+---------------------+

Here’s what happens when we provide π (pi):

SELECT 
    PI(),
    COS(PI());

Result:

+----------+-----------+
| PI()     | COS(PI()) |
+----------+-----------+
| 3.141593 |        -1 |
+----------+-----------+

Non-Numeric Arguments

Here’s an example of what happens when we provide a non-numeric argument:

SELECT COS('Cat');

Result:

+------------+
| COS('Cat') |
+------------+
|          1 |
+------------+
1 row in set, 1 warning (0.010 sec)

Let’s check the warning:

SHOW WARNINGS;

Result:

+---------+------+-----------------------------------------+
| Level   | Code | Message                                 |
+---------+------+-----------------------------------------+
| Warning | 1292 | Truncated incorrect DOUBLE value: 'Cat' |
+---------+------+-----------------------------------------+

Null Arguments

COS() returns null if the argument is null:

SELECT COS(null);

Result:

+-----------+
| COS(null) |
+-----------+
|      NULL |
+-----------+

Missing Arguments

Calling COS() with the wrong number of arguments, or without any arguments results in an error:

SELECT COS();

Result:

ERROR 1582 (42000): Incorrect parameter count in the call to native function 'COS'

And:

SELECT COS(10, 2);

Result:

ERROR 1582 (42000): Incorrect parameter count in the call to native function 'COS'