> -----Original Message----- > From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general- > owner@xxxxxxxxxxxxxx] On Behalf Of Juan Daniel Santana Rodés > Sent: Tuesday, September 17, 2013 11:00 AM > To: pgsql-general@xxxxxxxxxxxxxx > Subject: How to compare the results of two queries? > > I am developing a task in which I need to know how to compare the results of > two queries ... > I thought about creating a procedure which both queries received by > parameters respectively. Then somehow able to run queries and return if > both have the same result. As a feature of the problem, both queries are > selection. > Here I leave a piece of code I want to do. > > create or replace function compare(sql1 character varying, sql2 character > varying) returns boolean as $body$ Declare Begin --here in some way to run > both queries and then compare End; $body$ language 'plpgsql'; > > I've been studying and I found that there EXECUTE but to use it, first you > should have used PREPARE, and in this case the values of the parameters are > already made inquiries. > For example the execution of the function would be something like ... > > select compare('select * from table1', 'select * from table2'); > > For this case the result is false, then the queries are executed on different > tables. > Thanks in advance. > Best regards from Cuba. EXECUTE in PgPlsql does not require PREPARE. So, something like this: create or replace function compare(sql1 character varying, sql2 character varying) returns boolean as $body$ Declare lCount int := 0; Begin EXECUTE 'SELECT COUNT(Res.*) FROM ( (' || sql1 || ' EXCEPT ' || sql2 || ') UNION (' || sql2 || ' EXCEPT ' || sql1 || ') ) Res' INTO lCount; IF (lCount = 0) RETURN TRUE; ELSE RETURN FALSE; END IF; End; $body$ language 'plpgsql'; should work. Be aware, I didn't test it. Regards, Igor Neyman -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
