In Postgresql, Lateral Joins enable function chaining for set returning functions. ie you can feed the results of earlier srf function to the arguments of following function.
This gets around one of Postgresql most glaring omissions - table valued parameters. Is incredibly useful once you get used to them.
I might be misunderstanding your point, but Postgresql functions can take (and return) tables:
CREATE FUNCTION fullname(person) RETURNS TEXT AS $$
SELECT $1.firstname || ' ' || $1.lastname
$$ LANGUAGE SQL
Could you go into a more detail wrt using lateral joins with set returning functions? I'm used to using them as a way to "extend" the row with later terms depending on prior terms as you say, but I'm not comprehending the srf case so well (or tbh the results that pop up when I search for "posrgresql set returning function").
In my experience itβs relatively rare that you need them. I think of them as the for-each of joins. It evaluates row by row, not a single time. Another analogy would be a correlated subquery.
