Function creation syntax in PostgreSQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic syntax to create a function in PostgreSQL?

Use <code>CREATE FUNCTION function_name(parameters) RETURNS return_type AS $$ function_body $$ LANGUAGE language_name;</code> to define a function.

beginner

What keyword specifies the programming language used inside a PostgreSQL function?

The LANGUAGE keyword specifies the language, for example, LANGUAGE plpgsql or LANGUAGE sql.

beginner

How do you specify the return type of a PostgreSQL function?

Use the RETURNS clause followed by the data type, like RETURNS integer or RETURNS void.

intermediate

What is the purpose of the $$ symbols in PostgreSQL function creation?

They are dollar-quoting delimiters that mark the start and end of the function body, allowing you to include single quotes inside without escaping.

intermediate

Can a PostgreSQL function return a table? If yes, how is it declared?

Yes, by specifying RETURNS TABLE(column1 type1, column2 type2, ...) in the function signature.

Which keyword is used to start creating a function in PostgreSQL?

A CREATE FUNCTION

B DEFINE FUNCTION

C MAKE FUNCTION

D FUNCTION CREATE

The correct syntax starts with CREATE FUNCTION.

What does the RETURNS clause specify in a PostgreSQL function?

A The function's input parameters

B The function's language

C The function's return data type

D The function's name

The RETURNS clause defines the data type the function will return.

What is the purpose of the LANGUAGE clause in a PostgreSQL function?

A To specify the language of the operating system

B To specify the language of the database

C To specify the language of the client

D To specify the programming language used inside the function

It tells PostgreSQL which programming language the function code is written in.

Which of the following is a valid way to delimit the function body in PostgreSQL?

A Single quotes ' '

B Dollar quoting $$ $$

C Double quotes " "

D Backticks ` `

Dollar quoting with $$ allows including single quotes inside the function body without escaping.

How do you declare a function that returns multiple columns as a table in PostgreSQL?

A RETURNS TABLE(column1 type1, column2 type2)

B RETURNS MULTI

C RETURNS ARRAY

D RETURNS SETOF type

Use RETURNS TABLE with column definitions to return multiple columns.

Explain the basic syntax to create a function in PostgreSQL including how to specify parameters, return type, and language.

Think about the order and keywords used in the function creation statement.

Describe how you can create a PostgreSQL function that returns a table with multiple columns.

Focus on the RETURNS part and how to define multiple columns.