# How the PI() function works in Mariadb?

The `PI()`

function is a built-in function in Mariadb that returns the value of the mathematical constant pi, which is approximately 3.14159.

The `PI()`

function is a built-in function in Mariadb that returns the value of the mathematical constant pi, which is approximately 3.14159. The function is useful for performing calculations involving circles, angles, trigonometry, and other fields of mathematics. The function is also known as `PI`

.

## Syntax

The syntax of the `PI()`

function is as follows:

```
PI()
```

The function does not take any arguments. The function returns a decimal value that is the value of pi.

## Examples

### Example 1: Getting the value of pi with the PI() function

The following example shows how to use the `PI()`

function to get the value of pi:

```
SELECT PI() AS Pi;
```

The output is:

```
+----------+
| Pi |
+----------+
| 3.141593 |
+----------+
```

The function returns the value of pi, which is 3.14159265358979.

### Example 2: Calculating the area of a circle with the PI() function

The following example shows how to use the `PI()`

function to calculate the area of a circle with a given radius:

```
SELECT PI() * POWER(5, 2) AS Area;
```

The output is:

```
+-------------------+
| Area |
+-------------------+
| 78.53981633974483 |
+-------------------+
```

The function returns the area of a circle with a radius of 5, which is 78.5398. The formula for the area of a circle is $$\pi r^2$$, where $$r$$ is the radius.

### Example 3: Calculating the circumference of a circle with the PI() function

The following example shows how to use the `PI()`

function to calculate the circumference of a circle with a given radius:

```
SELECT 2 * PI() * 5 AS Circumference;
```

The output is:

```
+---------------+
| Circumference |
+---------------+
| 31.415927 |
+---------------+
```

The function returns the circumference of a circle with a radius of 5, which is 31.4159. The formula for the circumference of a circle is $$2\pi r$$, where $$r$$ is the radius.

## Related Functions

There are some other functions in Mariadb that are related to the `PI()`

function. They are:

`SIN()`

: This function returns the sine of a given angle in radians. The function is useful for calculating the ratio of the opposite side to the hypotenuse of a right triangle. The function is also known as`SINE()`

.`COS()`

: This function returns the cosine of a given angle in radians. The function is useful for calculating the ratio of the adjacent side to the hypotenuse of a right triangle. The function is also known as`COSINE()`

.`TAN()`

: This function returns the tangent of a given angle in radians. The function is useful for calculating the ratio of the opposite side to the adjacent side of a right triangle. The function is also known as`TANGENT()`

.

## Conclusion

The `PI()`

function is a useful function in Mariadb that allows you to get the value of the mathematical constant pi, which is approximately 3.14159. The function is helpful for performing calculations involving circles, angles, trigonometry, and other fields of mathematics. You can also use other functions like `SIN()`

, `COS()`

, and `TAN()`

to perform trigonometric operations with the value of pi. I hope this article helped you understand how the `PI()`

function works in Mariadb.