Database Design For reporting comparison results [closed] - sql-server

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We are going to design an table architecture. Here I wanted to compare same kind of data coming from different sources say Source_A and Source_B. I have to compare few attributes and identify below cases
Mismatches in attribute1
Mismatches in attribute2
Data that are missing in source_A
Data that are missing in Source_B.
Finally i have report to the same in PowerBI with charts. For now I have 2 tables A_DATA and B_DATA to store the incoming data and both are having below structure (this is just a sample, I have lot more columns)
+---------------+
| Columns |
+---------------+
| Material_ID |
+---------------+
| Material_Name |
+---------------+
| Material_Type |
+---------------+
| Quantity |
+---------------+
Now I'm confused whether should I create separate table for 4 cases(Mismatch,Source_A missing,Source_B Missing) or In single table I should have one more column saying Status and keep everything there. For reporting in PowerBI (like out of 1K rows, 5K are mismatches). Please suggest which one is better for reporting cases. Im really confused.

Answer 1

I would say neither of your two options (additional column, or new table) are optimal. I think this would be best handled with a view. Something like:
CREATE VIEW MisMatches
AS
SELECT Material_ID = ISNULL(a.Material_ID, b.Material_ID),
Status = CASE WHEN a.Material_ID IS NULL THEN 'Mising A'
WHEN b.Material_ID IS NULL THEN 'Mising B'
WHEN a.Material_Name <> b.Material_Name THEN 'Mismatch Name'
WHEN a.Material_Type <> b.Material_Type THEN 'Mismatch Type'
WHEN a.Quantity <> b.Quantity THEN 'Mismatch Quantity'
END,
MaterialName_A = a.Material_Name,
MaterialName_B = b.Material_Name,
Material_Type_A = a.Material_Type,
Material_Type_B = b.Material_Type,
Quantity_A = a.Quantity,
Quantity_B = b.Quantity
FROM A_Data AS a
FULL JOIN B_Data AS b
ON b.Material_ID = a.Material_ID
WHERE CHECKSUM(a.Material_Name, a.Material_Type, a.Quantity) <> CHECKSUM(b.Material_Name, b.Material_Type, b.Quantity);
This short circuits on your status column which may not be what you want, that is to say that if you name, quantity and type all don't match, then the status will only tell you that the name is a mismatch. If you want all mis-matches you will need to extend the case expression slightly. Also, if any of your columns are nullable, you will need to handle this in the Status case expression, e.g.
WHEN a.Quantity <> b.Quantity OR a.Quantity IS NULL OR b.Quantity IS NULL THEN ...
I have also had to make an assumption about how you identify a match, but hopefully this gives the general gist of it
Edit
There is a better way of doing this rather than CHECKSUM:
CREATE VIEW MisMatches
AS
SELECT Material_ID = ISNULL(a.Material_ID, b.Material_ID),
Status = CASE WHEN a.Material_ID IS NULL THEN 'Mising A'
WHEN b.Material_ID IS NULL THEN 'Mising B'
WHEN a.Material_Name <> b.Material_Name THEN 'Mismatch Name'
WHEN a.Material_Type <> b.Material_Type THEN 'Mismatch Type'
WHEN a.Quantity <> b.Quantity THEN 'Mismatch Quantity'
END,
MaterialName_A = a.Material_Name,
MaterialName_B = b.Material_Name,
Material_Type_A = a.Material_Type,
Material_Type_B = b.Material_Type,
Quantity_A = a.Quantity,
Quantity_B = b.Quantity
FROM A_Data AS a
FULL JOIN B_Data AS b
ON b.Material_ID = a.Material_ID
WHERE NOT EXISTS
( SELECT a.Material_Name, a.Material_Type, a.Quantity
INTERSECT
SELECT b.Material_Name, b.Material_Type, b.Quantity
);
I discovered this read the following article: Undocumented Query Plans: Equality Comparisons