That is correct. The function I've written only works when the two tables are named table_train and table_test; is it possible to generalize that to take in any two tables?
I'm a novice plpgsql user. For an application, I'm trying to write a user-defined function that takes a row of some table (let's say with k fields) and takes another row from another table (again with k fields); then calculate the Euclidean, Manhattan or generally Minkowski distance (with some p) and then return an integer. I've written this:
CREATE FUNCTION euclidean_distance(row1 table_train, row2 table_test, OUT distance DOUBLE PRECISION) AS $$ DECLARE tmp DOUBLE PRECISION; BEGIN FOR col IN SELECT column_name FROM information_schema.columns WHERE table_name=table_train LOOP tmp := (row1.col - row2.col); distance += tmp*tmp; END LOOP; distance := sqrt(distance); END; $$ LANGUAGE plpgsql;
Could anyone please help me fix this function so that I can pass any two rows of two tables (with same number of columns) and have their distance returned.
You are already doing that, so do you mean any two rows of any two tables?
