drop extension if exists pg_query_rewrite;
NOTICE:  extension "pg_query_rewrite" does not exist, skipping
--
create extension pg_query_rewrite;
select pgqr_truncate();
 pgqr_truncate 
---------------
 t
(1 row)

--
select pgqr_add_rule('select 10;','select 11;');
 pgqr_add_rule 
---------------
 t
(1 row)

--
select 10;
 ?column? 
----------
       11
(1 row)

--
drop extension pg_query_rewrite;