> ## Documentation Index > Fetch the complete documentation index at: https://docs.streamnative.io/llms.txt > Use this file to discover all available pages before exploring further. # Built-in UDFs This feature is currently in alpha. If you want to try it out or have any questions, [submit a ticket](https://support.streamnative.io/hc/en-us/requests/new) to the support team. ## Built-in Common UDFs ### Data Type Conversion Function The pfSQL `cast` function is used to convert a value from one data type to another. Currently, it supports 6 data types, including `INT32`, `INT64`, `FLOAT`, `DOUBLE`, `STRING`, and `BOOLEAN`. The syntax of the `cast` function is: ```sql theme={null} SELECT cast(field1, to=int32) from topic ``` The `cast` function takes two parameters, the first one is the field name, and the second one is the target data type. The target data type is specified by the `to` keyword, and it can be one of the following values: * "int32" * "int64" * "float" * "double" * "string" * "boolean" The conversion rules to be followed are shown in the following table. | | int32 | int64 | float | double | string | boolean | | ------- | -------------------------------------------------------------------- | -------------------------------------------------------------------- | ------------------------------------------------------------------- | ---------------------- | ------------------------- | ----------------------------------------------------------------------------------------------------- | | int32 | No need to cast | Cast directly | Cast directly | Cast directly | `String.valueOf` | `!=0 : true, ==0: false` | | int64 | Out of the range of INT32: throw Exception, otherwise cast directly | No need to cast | Cast directly | Cast directly | `String.valueOf` | `!=0L : true, ==0L: false` | | float | Out of the range of INT32: throw Exception, otherwise `Math.round()` | Out of the range of INT64: throw Exception, otherwise `Math.round()` | No need to cast | Cast directly | `String.valueOf` | `!=0.0f : true, ==0.0f: false` | | double | Out of the range of INT32: throw Exception, otherwise `Math.round()` | Out of the range of INT64: throw Exception, otherwise `Math.round()` | Out of the range of FLOAT: throw Exception, otherwise cast directly | No need to cast | `String.valueOf` | `!=0.0 : true, ==0.0: false` | | string | `Integer.parseInt()` | `Long.parseLong()` | `Float.parseFloat()` | `Double.parseDouble()` | No need to cast | `text.toLowerCase ==”true”` : true, `text.toLowerCase == “false”` : false, otherwise: throw Exception | | boolean | `bool ? 1 : 0` | `bool ? 1L : 0L` | `bool ? 1.0f : 0.0f` | `bool ? 1.0 : 0.0` | `bool ? "true" : "false"` | No need to cast | ### Const Value Function The pfSQL `const` function is used to return a constant value. The syntax of the `const` function is: ```sql theme={null} SELECT const(value=val, type=typ) from topic ``` The `const` function takes two parameters, the first one is the constant value, and the second one is the data type of the constant value. The data type is specified by the `type` keyword, and it can be one of the following values: * "int32" * "int64" * "float" * "double" * "string" * "boolean" The following example shows how to use the `const` function: ```sql theme={null} SELECT const(value=1, type=int32) from topic ``` The above SQL statement returns a constant value of type `int32` with value `1`. ## Built-in Math UDFs Currently, pfSQL supports the following mathmatical functions. The behavior of these mathmatical functions is identical to the behavior of the corresponding functions in the Java Math standard library. | Function Name | Allowed input schema types | Output schema type | attributes parameter | Corresponding Java Math function | | ------------- | ------------------------------ | ---------------------- | -------------------- | --------------------------------------------------------------------- | | sin | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#sin(double)` | | cos | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#cos(double)` | | tan | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#tan(double)` | | asin | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#asin(double)` | | acos | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#acos(double)` | | atan | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#atan(double)` | | sinh | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#sinh(double)` | | cosh | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#cosh(double)` | | tanh | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#tanh(double)` | | degrees | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#toDegrees(double)` | | radians | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#toRadians(double)` | | abs | INT32 / INT64 / FLOAT / DOUBLE | Same type as the input | - | `Math#abs(int) / Math#abs(long) / Math#abs(float) / Math#abs(double)` | | ceil | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#ceil(double)` | | floor | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#floor(double)` | | exp | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#exp(double)` | | ln | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#log(double)` | | log10 | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#log10(double)` | | sqrt | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#sqrt(double)` | | sign | INT32 / INT64 / FLOAT / DOUBLE | DOUBLE | - | `Math#signum(double)` | The syntax of the mathmatical functions is: ```sql theme={null} SELECT field1, sin(field2), cos(field3), tan(field4) as tan from topic ``` ## Limitations 1. The UDF only support in SELECT statement, we are working on it to extend the UDF to WHERE and other statements. 2. The UDF only support passing full path of single field in SELECT statement yet.