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

--
drop table if exists t;
NOTICE:  table "t" does not exist, skipping
create table t(x int, y int);
--
insert into t values(1,2);
--
select pgqr_add_rule('select 10;','select 11;');
 pgqr_add_rule 
---------------
 t
(1 row)

select pgqr_add_rule('select 1+1;','select 1+2;');
 pgqr_add_rule 
---------------
 t
(1 row)

select pgqr_add_rule('select x from t;','select x,y from t;');
 pgqr_add_rule 
---------------
 t
(1 row)

select pgqr_add_rule('delete from t;','delete from t where 1=0;');
 pgqr_add_rule 
---------------
 t
(1 row)

select pgqr_add_rule('update t set x=y;','update t set x=y where 1=0;');
 pgqr_add_rule 
---------------
 t
(1 row)

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

select 1+1;
 ?column? 
----------
        3
(1 row)

select x from t;
 x | y 
---+---
 1 | 2
(1 row)

begin;
delete from t;
select * from t;
 x | y 
---+---
 1 | 2
(1 row)

rollback;
select * from t;
 x | y 
---+---
 1 | 2
(1 row)

begin;
update t set x=y;
select * from t;
 x | y 
---+---
 1 | 2
(1 row)

rollback;
select * from t;
 x | y 
---+---
 1 | 2
(1 row)