#
# Table elimination (MWL#17) tests
#
--disable_warnings
drop table if exists t0, t1, t2, t3;
--enable_warnings

create table t1 (a int);
insert into t1 values (0),(1),(2),(3);
create table t0 as select * from t1;

create table t2 (a int primary key, b int) 
  as select a, a as b from t1 where a in (1,2);

create table t3 (a int primary key, b int) 
  as select a, a as b from t1 where a in (1,3);

--echo # This will be  eliminated:
explain select t1.a from t1 left join t2 on t2.a=t1.a;
explain extended select t1.a from t1 left join t2 on t2.a=t1.a;

select t1.a from t1 left join t2 on t2.a=t1.a;

--echo # This will not be eliminated as t2.b is in in select list:
explain select * from t1 left join t2 on t2.a=t1.a;

--echo # This will not be eliminated as t2.b is in in order list:
explain select t1.a from t1 left join t2 on t2.a=t1.a order by t2.b;

--echo # This will not be eliminated as t2.b is in group list:
explain select t1.a from t1 left join t2 on t2.a=t1.a group by t2.b;

--echo # This will not be eliminated as t2.b is in the WHERE
explain select t1.a from t1 left join t2 on t2.a=t1.a where t2.b < 3 or t2.b is null;

--echo # Elimination of multiple tables:
explain select t1.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a;

--echo # Elimination of multiple tables (2):
explain select t1.a from t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a;

--echo # Elimination when done within an outer join nest:
explain extended
select t0.*
from
  t0 left join (t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and
  t3.a=t1.a) on t0.a=t1.a;

--echo # Elimination with aggregate functions
explain select count(*) from t1 left join t2 on t2.a=t1.a;
explain select count(1) from t1 left join t2 on t2.a=t1.a;
explain select count(1) from t1 left join t2 on t2.a=t1.a group by t1.a;

--echo This must not use elimination:
explain select count(1) from t1 left join t2 on t2.a=t1.a group by t2.a;

drop table t0, t1, t2, t3;