pg learning

CREATE OR REPLACE FUNCTION getTable(rows INTEGER)
RETURNS TABLE(col1 INTEGER, col2 TEXT)
AS $$
BEGIN
RETURN QUERY SELECT i * 2, i || '_text'
FROM generate_series(1, rows, 1) as t(i);
END;
$$ LANGUAGE PLPGSQL;

https://www.cnblogs.com/winkey4986/p/6437811.html

pg recursive queries
https://www.jb51.net/article/161399.htm