SAMPLE.txt

CREATE OR REPLACE FUNCTION add_pseudo_column()
RETURNS TABLE (
    id INT,
    date DATE,
    name VARCHAR,
    value DOUBLE PRECISION,
    description TEXT,
    pseudo_column DOUBLE PRECISION
) AS $$
BEGIN
    RETURN QUERY
    SELECT sample_data.id, sample_data.date, sample_data.name, sample_data.value, sample_data.description, NULL::double precision AS pseudo_column
    FROM sample_data;
END;
$$ LANGUAGE plpgsql;



CREATE TABLE sample_data (
    id SERIAL PRIMARY KEY,
    date DATE,
    name VARCHAR(50),
    value DOUBLE PRECISION,
    description TEXT
);
SELECT * FROM add_pseudo_column();

INSERT INTO sample_data (date, name, value, description) VALUES
('2023-01-01', 'Sample 1', 100.0, 'This is a sample description 1'),
('2023-01-02', 'Sample 2', 150.0, 'This is a sample description 2'),
('2023-01-03', 'Sample 3', 200.0, 'This is a sample description 3'),
('2023-01-04', 'Sample 4', 250.0, 'This is a sample description 4'),
('2023-01-05', 'Sample 5', 300.0, 'This is a sample description 5');