SQL Creating multiple columns in View from one single table-column - sql

Question

I'm trying to create a View in SQL Server 2008 R2, where data is extracted from two tables with dual one-to-one relationships, and I want to create two columns in the view based values from a single column in one of the tables.
The tables are currently similar to these examples:
TableA:
PrimaryKey | Name | Value_FK | Number_FK
-------------------------------------------
66 | NameA | 1 | 2
77 | NameB | 3 | 4
TableB:
PrimaryKey | Value
-------------------
1 | 238
2 | 456
3 | 100
4 | 200
The View should look like this:
Name | Value | Number
-------------------------
NameA | 238 | 456
NameB | 100 | 200
('Value' and 'Number' are essentially the same type, and are both found in the 'Value' column in TableB. I thought it would be more easy to distingiush between 'Value' and 'Number', than 'ValueA' and 'ValueB').
The factor that should decide which values go into Column 'Value' or Column 'Number' is the PrimaryKey in TableB and its references in either foreignkey in TableA (but both FKs shall NEVER refer to the same key).
This is likely not the most brilliant database model, having dual relationships between to tables. This is however due to mapping some C#.NET classes to a database by using ADO.NET Entity Framework, where Class A has two objects of Class B (in this case named 'Value' and 'Number'), and the database model currently constructs two relationships becuase of this. Changing this is not an option.
I've tried googling this, but I find it difficult to find an answer that I need. Especially when most results are about the opposite: Selecting multiple columns into one column.
So, how should I write the Select statement?
CREATE VIEW ViewName
AS
SELECT DISTINCT a.Name as 'Name', ????? as 'Value', ????? as 'Number'
FROM TableA a, TableB b
I am quite rusty with advanced SQL-commands. It's been over 1,5 years since last I was into something this advanced. I tried something similar to this first:
CREATE VIEW ViewName
AS
WITH Name AS
( SELECT DISTINCT a.Name FROM TableA a )
Value AS
(
SELECT DISTINCT b.Value as 'Value' FROM TableA a, TableB b
WHERE b.PrimaryKey = an.ValueA_FK
),
Number AS
(
SELECT DISTINCT b.Value as 'Number'
FROM TableA a, TableB b
WHERE a.PrimaryKey = an.ValueB_PrimaryKey
)
SELECT DISTINCT
* FROM Name, Value, Number
The result of my utterly failed attempt is like this:
Name | Value | Number
-------------------------
NameA | 100 | 200
NameB | 100 | 200
NameA | 100 | 456
NameB | 100 | 456
NameA | 238 | 200
NameB | 238 | 200
NameA | 238 | 456
NameB | 238 | 456
Now, any suggestiong as what to fill in the query?

Answer 1

You can reference the same table more than once in the FROM clause:
SELECT a.Name as 'Name', b1.Value as 'Value', b2.Value as 'Number'
FROM TableA a
inner join TableB b1
on
a.Value_FK = b1.PrimaryKey
inner join TableB b2
on
a.Number_FK = b2.PrimaryKey
I've also removed the DISTINCT, since it shouldn't be your habit to add one, and there's nothing in the question that suggests one is necessary. I've also used ANSI-Style joins. These are almost always to be preferred over the older style (where tables in the FROM clause are just separated by commas)
If it's possible that some rows in TableA have a NULL Value_FK or Number_FK, and you still want those rows in your view, you would switch one or both of the inner joins to be left joins. You would then also decide whether the output column should be NULL (in which case you're done) or some other value (in which case, you would have e.g. COALESCE(b1.Value,<Value when null>) as 'Value').

Answer 2

This query will yield results you want:
select t1.Name, value.Value, number.Value as Number
from TableA t1
inner join TableB value on value.PrimaryKey = t1.Value_FK
inner join TableB number on number.PrimaryKey = t1.Number_FK
you over-complicated your query a lot.