# PI

> Retrieve the mathematical constant π (pi) using SQL in StackQL.

Source: https://stackql.io/language-spec/functions/math/trigonometric/pi

Returns the mathematical constant π (pi), which is the ratio of a circle's circumference to its diameter.

See also:  
[[`SELECT`]](/language-spec/select) 

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## Syntax

```sql
SELECT PI() AS pi_value;
```

## Arguments

This function does not require any arguments.

## Return Value(s)
Returns the constant π, approximately equal to 3.14159.

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## Examples

### Retrieve the value of π

```sql
SELECT PI() AS pi_value;
```

This query will output the value of π, which is approximately `3.14159`, useful in various mathematical calculations involving circles and other geometric functions.