SQL INNER JOIN duplicates to be remove based on criteria - sql

Question

I have the below two tables:
Table 1
┌──────────┬────────────┬───────────────┐
│ account1 │ Fruit_name │ First_harvest │
├──────────┼────────────┼───────────────┤
│ 567 │ Apple │ 201805 │
│ 432 │ Mango │ 201809 │
│ 567 │ Apple │ 201836 │
└──────────┴────────────┴───────────────┘
Table 2
┌──────────┬─────────────┬──────────────┬───────────────┬──────────────┬─────────────┐
│ account1 │ Fruit_name │ Current_Farm │ Previous_Farm │ FirstHarvest │ LastHarvest │
├──────────┼─────────────┼──────────────┼───────────────┼──────────────┼─────────────┤
│ 567 │ Apple │ APFarm │ AppleYard │ 201801 │ 201810 │
│ 567 │ Apple │ APFarm │ FruitFarm │ 201805 │ 201830 │
│ 567 │ Apple │ APFarm │ FruitMarket │ 201831 │ 999999 │
│ 567 │ Royal Gala │ APFarm │ GrocerWorld │ 201815 │ 999999 │
└──────────┴─────────────┴──────────────┴───────────────┴──────────────┴─────────────┘
My code:
SELECT DISTINCT a.account1,a.fruit_name,Max(a.first_harvest) first_harvest,b.current_farm,b.previous_farm,b.firstharvest,b.lastharvest
FROM fruit_harvest_data a
INNER JOIN fruit_farm_data b
ON a.account1 = b.account1
AND CASE WHEN b.fruit_name = 'Apple' THEN 'Royal Gala'
ELSE b.fruit_name END =
CASE WHEN a.fruit_name = 'Apple' THEN 'Royal gala'
ELSE a.fruit_name END
WHERE a.first_harvest BETWEEN b.firstharvest AND b.lastharvest
GROUP BY a.account1,a.fruit_name,b.current_farm,b.previous_farm,b.firstharvest,b.lastharvest
HAVING Max(a.first_harvest) >= 201801
Result:
┌──────────┬────────────┬───────────────┬──────────────┬───────────────┬──────────────┬─────────────┐
│ account1 │ Fruit_name │ First_harvest │ Current_Farm │ Previous_Farm │ FirstHarvest │ LastHarvest │
├──────────┼────────────┼───────────────┼──────────────┼───────────────┼──────────────┼─────────────┤
│ 567 │ Apple │ 201836 │ APFarm │ FruitMarket │ 201831 │ 999999 │
│ 567 │ Royal Gala │ 201836 │ APFarm │ GrocerWorld │ 201815 │ 999999 │
└──────────┴────────────┴───────────────┴──────────────┴───────────────┴──────────────┴─────────────┘
Request:
I get duplicate data due to the way we have this stored. Is there a
way to only show the result if account1 has both Apple and Royal Gala then it should only select Royal Gala.
Please note: account1 eg., 567 can have multiple fruits like apple, roya gal, mango, orange. but should only select Royal gala in case if exists in both apple and royal gala.

Answer 1

I think below should work
select distinct T.* from
(SELECT DISTINCT a.account1,
case when a.fruit_name='Apple' or a.fruit_name='Royal Gala' then
'Apple' else a.fruit_name end as fruit_name ,Max(a.first_harvest) first_harvest,b.current_farm,b.previous_farm,b.firstharvest,b.lastharvest
FROM fruit_harvest_data a
INNER JOIN fruit_farm_data b
ON a.account1 = b.account1
AND CASE WHEN b.fruit_name = 'Apple' THEN 'Royal Gala'
ELSE b.fruit_name END =
CASE WHEN a.fruit_name = 'Apple' THEN 'Royal gala'
ELSE a.fruit_name END
WHERE a.first_harvest BETWEEN b.firstharvest AND b.lastharvest
GROUP BY a.account1,a.fruit_name,b.current_farm,b.previous_farm,b.firstharvest,b.lastharvest
HAVING Max(a.first_harvest) >= 201801
) as T

Answer 2

Still unclear about what you want in your result set - a more complete desired result would help, but to answer the question as to how to do it:
Since you have mentioned that Apple/Gala is an example, I would create a new table to contain these pairs:
create table replace_list(oldfruit varchar(20), newfruit varchar(20))
insert replace_list values ('Apple','Royal Gala')
Then in your query add this:
left join replace_list r on r.oldfruit=b.fruit_name
left join fruit_farm_data n on n.account1=a.account1 and n.fruit_name=newfruit
and in your where clause, you will check where either the fruit name does not have a replacement r.oldfruit is null or it does have a replacement, but the farm doesnt have that fruit n.fruit_name is null
where r.oldfruit is null or n.fruit_name is null
The rest of the query you can work out for yourself.