Hive: work around for non equi left join - join

Question

Hive does not support non equi joins: The common work around is to move the join condition to the where clause, which work fine when you want an inner join. but what about a left join?
Contrived example. Let say we have an orderLineItem table, and we need to join to a ProductPrice table that has a productID, price & a date range for which the price applies. We want to join to this where ProductID=ProductID & OrderDate between start and End date. If a productID or a valid date range do not match, I'd still want to see all orderLineItems.
This SQL fiddle is an example of how we'd do this in MSSQL:
http://sqlfiddle.com/#!6/fb877/7
Problem
If I apply the typical workaround, and move the non equi filter to the where clause, it becomes an inner join. In the case above, in the sql fiddle & below, I have a product ID that is not in the lookup.
Question:
Provided hive does not support non eqi-joins, How can a left non-eqi be achieved ?
[SQLFiddle Content]
Tables:
CREATE TABLE OrderLineItem(
LineItemIDId int IDENTITY(1,1),
OrderID int NOT NULL,
ProductID int NOT NULL,
OrderDate Date
);
CREATE TABLE ProductPrice(
ProductID int,
Cost float,
startDate Date,
EndDate Date
);
loading The data & how we'd join in MSSQL:
--Old Price. Should be ignored
INSERT INTO ProductPrice(ProductID, COST,startDate,EndDate) VALUES (1, 50,'12/1/2012','1/1/2013');
INSERT INTO ProductPrice(ProductID, COST,startDate,EndDate) VALUES (2, 55,'12/1/2012','1/1/2013');
--Price for Order 2. Should be applied to Order 1
INSERT INTO ProductPrice (ProductID, COST,startDate,EndDate) VALUES(1, 20,'12/1/2013','1/1/2014');
INSERT INTO ProductPrice (ProductID, COST,startDate,EndDate) VALUES(2, 25,'12/1/2013','1/1/2014');
--Price for Order 2. Should be applied to Order 2
INSERT INTO ProductPrice (ProductID, COST,startDate,EndDate) VALUES(1, 15,'1/2/2014','3/1/2014');
INSERT INTO ProductPrice (ProductID, COST,startDate,EndDate) VALUES(2, 20,'1/2/2014','3/1/2014');
--January 1st 2014 Order
INSERT INTO OrderLineItem(OrderID,ProductID,OrderDate) VALUES (1, 1,'1/1/2014') ;
INSERT INTO OrderLineItem(OrderID,ProductID,OrderDate) VALUES (1, 2,'1/1/2014');
--Feb 1st 2014 Order
INSERT INTO OrderLineItem(OrderID,ProductID,OrderDate) VALUES (2, 1,'2/1/2014');
INSERT INTO OrderLineItem (OrderID,ProductID,OrderDate) VALUES(2, 2,'2/1/2014');
INSERT INTO OrderLineItem (OrderID,ProductID,OrderDate) VALUES(2, 3,'2/1/2014'); -- no price
SELECT * FROM OrderLineItem;
SELECT * FROM OrderLineItem li LEFT OUTER JOIN ProductPrice p on
p.ProductID=li.ProductID AND OrderDate BETWEEN startDate AND EndDate;

Answer 1

Create a copy of the left table with added serial row numbers:
CREATE TABLE OrderLineItem_serial AS
SELECT ROW_NUMBER() OVER() AS serial, * FROM OrderLineItem;
Remark: This may work better for some tables formats (must be WITHOUT COMPRESSION):
CONCAT(INPUT__FILE__NAME, BLOCK__OFFSET__INSIDE__FILE) AS serial
Do an inner join:
CREATE TABLE OrderLineItem_inner AS
SELECT * FROM OrderLineItem_serial li JOIN ProductPrice p
on p.ProductID = li.ProductID WHERE OrderDate BETWEEN startDate AND EndDate;
Left join by serial:
SELECT * FROM OrderLineItem_serial li
LEFT OUTER JOIN OrderLineItem_inner i on li.serial = i.serial;

Answer 2

Why not use a WHERE clause that allows for NULL cases separately?
SELECT * FROM OrderLineItem li
LEFT OUTER JOIN ProductPrice p
ON p.ProductID=li.ProductID
WHERE ( StartDate IS NULL OR OrderDate BETWEEN startDate AND EndDate);
That should take care of it - if the left join matches it'll use the date logic, if it doesn't it'll keep the NULL values intact as a left join should.

Answer 3

Not sure if you can avoid using a double join:
SELECT *
FROM OrderLineItem li
LEFT OUTER JOIN (
SELECT p.*
FROM ProductPrice p
JOIN OrderLineItem li
ON p.ProductID=li.ProductID
WHERE OrderDate BETWEEN StartDate AND EndDate ) p
ON p.ProductId = li.ProductID
WHERE StartDate IS NULL OR
OrderDate BETWEEN StartDate AND EndDate;
This way if there is a match and StartDate is not null, there has to be a valid start/end date match.

Answer 4

Hive 0.10 supports cross joins, so you could handle all your "theta join" (non-equijoin) conditions in the WHERE clause.