CREATE FUNCTION

Define a function.

With CREATE FUNCTION you define SQL code that returns a value.

CREATE FUNCTION full_name(first VARCHAR, last VARCHAR)
RETURNS VARCHAR
LANGUAGE SQL
AS $$
  SELECT first || ' ' || last;
$$;

This query combines first and last name.

The function full_name is created. The expression first || ' ' || last is evaluated and returned.

CREATE FUNCTION — details

A function specifies its return type with RETURNS. The body goes between AS $$.

For example, RETURNS DECIMAL states that the function returns a decimal number; if the value doesn't fit that type the database raises an error.

Create a full_name function: combine first and last name.

Show example solution

CREATE FUNCTION full_name(first VARCHAR, last VARCHAR)
RETURNS VARCHAR
LANGUAGE SQL
AS $$
  SELECT first || ' ' || last;
$$;

Add RETURNS

CREATE FUNCTION full_name(first VARCHAR, last VARCHAR)
____ VARCHAR

Show answer

CREATE FUNCTION full_name(first VARCHAR, last VARCHAR)
RETURNS VARCHAR

Next lesson: RETURN