DROP TABLE IF EXISTS partsupp;
DROP TABLE IF EXISTS lineitem;
DROP TABLE IF EXISTS supplier;
DROP TABLE IF EXISTS nation;
DROP TABLE IF EXISTS q20_tmp1;
DROP TABLE IF EXISTS q20_tmp2;
DROP TABLE IF EXISTS q20_tmp3;
DROP TABLE IF EXISTS q20_tmp4;
DROP TABLE IF EXISTS q20_potential_part_promotion;

-- create tables and load data
create external table part (P_PARTKEY INT, P_NAME STRING, P_MFGR STRING, P_BRAND STRING, P_TYPE STRING, P_SIZE INT, P_CONTAINER STRING, P_RETAILPRICE DOUBLE, P_COMMENT STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS TEXTFILE LOCATION '/tpch/part';
create external table lineitem (L_ORDERKEY INT, L_PARTKEY INT, L_SUPPKEY INT, L_LINENUMBER INT, L_QUANTITY DOUBLE, L_EXTENDEDPRICE DOUBLE, L_DISCOUNT DOUBLE, L_TAX DOUBLE, L_RETURNFLAG STRING, L_LINESTATUS STRING, L_SHIPDATE STRING, L_COMMITDATE STRING, L_RECEIPTDATE STRING, L_SHIPINSTRUCT STRING, L_SHIPMODE STRING, L_COMMENT STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS TEXTFILE LOCATION '/tpch/lineitem';
create external table supplier (S_SUPPKEY INT, S_NAME STRING, S_ADDRESS STRING, S_NATIONKEY INT, S_PHONE STRING, S_ACCTBAL DOUBLE, S_COMMENT STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS TEXTFILE LOCATION '/tpch/supplier';
create external table nation (N_NATIONKEY INT, N_NAME STRING, N_REGIONKEY INT, N_COMMENT STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS TEXTFILE LOCATION '/tpch/nation';
create external table partsupp (PS_PARTKEY INT, PS_SUPPKEY INT, PS_AVAILQTY INT, PS_SUPPLYCOST DOUBLE, PS_COMMENT STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS TEXTFILE LOCATION'/tpch/partsupp';

-- create the target table
create table q20_tmp1(p_partkey int);
create table q20_tmp2(l_partkey int, l_suppkey int, sum_quantity double);
create table q20_tmp3(ps_suppkey int, ps_availqty int, sum_quantity double);
create table q20_tmp4(ps_suppkey int);
create table q20_potential_part_promotion(s_name string, s_address string);


-- the query
insert overwrite table q20_tmp1
select distinct p_partkey
from
  part 
where 
  p_name like 'forest%';

insert overwrite table q20_tmp2
select 
  l_partkey, l_suppkey, 0.5 * sum(l_quantity)
from
  lineitem
where
  l_shipdate >= '1994-01-01'
  and l_shipdate < '1995-01-01'
group by l_partkey, l_suppkey;

insert overwrite table q20_tmp3
select 
  ps_suppkey, ps_availqty, sum_quantity
from  
  partsupp ps join q20_tmp1 t1 
  on 
    ps.ps_partkey = t1.p_partkey
  join q20_tmp2 t2 
  on 
    ps.ps_partkey = t2.l_partkey and ps.ps_suppkey = t2.l_suppkey;

insert overwrite table q20_tmp4
select 
  ps_suppkey
from 
  q20_tmp3
where 
  ps_availqty > sum_quantity
group by ps_suppkey;

insert overwrite table q20_potential_part_promotion
select 
  s_name, s_address
from 
  supplier s join nation n
  on
    s.s_nationkey = n.n_nationkey
    and n.n_name = 'CANADA'
  join q20_tmp4 t4
  on 
    s.s_suppkey = t4.ps_suppkey
order by s_name;