Database Reference
In-Depth Information
• Default value assignment in the
function_identifier()
function:
variable_identifier := function_identifier(arguments);
• The
SELECT
statement in the
AVG(amount)
function:
SELECT AVG(amount) FROM history;
• The
SELECT
statement in the
getRecords()
function:
SELECT getRecords();
Similarly, values are returned with a
RETURN
statement.
The RETURN expression
As the function ends, the evaluated value of expression will be returned as per the
speciied return type in the
CREATE FUNCTION
command.
The syntax for the
RETURN
command is as follows:
CREATE OR REPLACE FUNCTION function_identifier(arguments)
RETURNS TYPE AS
DECLARE
declaration;
BEGIN
statement;
RETURN { variable_name | value }
END;
LANGUAGE 'plpgsql';
Exception handling statements
Programming languages provide an exception handling mechanism to handle errors
and reports for solution analysis. You can implement the
RAISE
statements to raise
errors and exceptions in the PL/pgSQL function as follows:
RAISE NOTICE ''amount value is small.'';
Error handling will be discussed later in this chapter.
Compound statements
Conditional or looping structures contain statements that are executed on the
evaluation of conditions.
