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?
Thanks in advance. >Babak On Mon, Apr 25, 2016 at 10:24 AM, Adrian Klaver <adrian.kla...@aklaver.com> wrote: > On 04/25/2016 07:07 AM, Babak Alipour wrote: > >> Greetings everyone, >> >> 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? > > >> Best regards, >> Babak Alipour >> >> -- >> */Babak Alipour ,/* >> */University of Florida/* >> > > > -- > Adrian Klaver > adrian.kla...@aklaver.com > -- *Babak Alipour ,* *University of Florida*
