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CREATE FUNCTION -user defined function (UDF)

Creates a user defined function (UDF) from a lambda expression. The expression must consist of function parameters, constants, operators, or other function calls.

Syntax

A function can have an arbitrary number of parameters.

There are a few restrictions:

  • The name of a function must be unique among user defined and system functions.
  • Recursive functions are not allowed.
  • All variables used by a function must be specified in its parameter list.

If any restriction is violated then an exception is raised.

Example

Query:

Result:

A conditional function is called in a user defined function in the following query:

Result:

Executable UDFs.

User-defined functions in ClickHouse Cloud