CODEWITHSUNDEEP
sql-servert-sqlsql-server-2008-r2
Erik
Erik

Reputation: 161

T-SQL Cross Join to get missing values

Here's a simple example of my problem. I have a stored proc that creates a report.

DECLARE @Report TABLE
(Product VARCHAR(10),
Purchases MONEY default (0) 
)
DECLARE @Range TABLE
(minP MONEY,
maxP MONEY,
Descrip VARCHAR(50)
)

INSERT @Range
VALUES(0,1,'0-1'),
(2,5,'2-5'),
(6,10,'6-10')

INSERT @Report(Product, Purchases)
VALUES('A',1),
('A',5),
('B',10)


SELECT r.Product, r.Purchases, x.Descrip  
FROM @Report r CROSS JOIN @Range x 
WHERE r.purchases BETWEEN x.minp AND x.maxp

The results look like this:

Product Purchases   Descrip
A   1.00    0-1
A   5.00    2-5
B   10.00   6-10

How can I get the results to look like this:

Product Purchases   Descrip
A   1.00    0-1
A   5.00    2-5
A   0   6-10
B   0   0-1
B   0   2-5
B   10.00   6-10

Upvotes: 4

Views: 2786

Answers (2)

mellamokb
mellamokb

Reputation: 56779

You could try something like this:

  • Cross join distinct list of products with ranges to get every combination.
  • Left join this cross-joined list with the original report raw data to fill in purchase data.
  • The join relationship will be the same logic as your original where clause (plus linking product)

Sample Query

SELECT
  r2.Product,
  coalesce(r.Purchases, 0) as Purchases,
  x.Descrip  
FROM 
  (select distinct Product from @Report) r2 CROSS JOIN @Range x
    left join @Report r on r.purchases BETWEEN x.minp AND x.maxp
                        and r.product = r2.product

Sample Output (DEMO):

| PRODUCT | PURCHASES | DESCRIP |
---------------------------------
|       A |         1 |     0-1 |
|       A |         5 |     2-5 |
|       A |         0 |    6-10 |
|       B |         0 |     0-1 |
|       B |         0 |     2-5 |
|       B |        10 |    6-10 |

I would assume your actual data is much more complicated than this. For instance, I'm not sure what kind of result you expect if there are multiple purchases within a single range. But this should at least get you started.

Upvotes: 3

Lamak
Lamak

Reputation: 70668

This should do it:

SELECT B.Product, ISNULL(C.Purchases,0) Purchases, A.Descrip
FROM @Range A
CROSS JOIN (SELECT DISTINCT Product
            FROM @Report) B
LEFT JOIN @Report C
    ON B.Product = C.Product 
    AND C.Purchases BETWEEN A.minP AND A.maxP
ORDER BY B.Product, Purchases

Here is a demo for you to try.

Upvotes: 4

Related Questions