Transact-SQL Query / How to combine multiple JOIN statements? - sql

Question

I'm banging my head on this SQL puzzle since a couple of hours already, so i thought to myself : "Hey, why don't you ask the Stack and allow the web to benefit from the solution?"
So here it is. First thing, these are my SQL tables:
Fields
FieldID INT (PK)
FieldName NVARCHAR(50) (IX)
FormFields
FieldID INT (FK)
FormID INT (FK)
Values
FieldID INT (FK)
RecordID INT (FK)
Value NVARCHAR(1000)
Forms
FormID INT (PK)
FormName NVARCHAR(50) (IX)
Records
RecordID INT (PK)
FormID INT (FK)
PoolID INT (FK)
DataPools
PoolID INT (PK)
FormID INT (FK)
PoolName NVARCHAR(50) (IX)
Consider the following constraints.
Each Form has 0 or more DataPool. Each DataPool can only be assigned to one Form.
Each Form has 0 or more Field. Each Field might be assigned to several Form.
Each Record has 0 or more Value. Each Value is linked to a single Record.
Each DataPool has 0 or more Record. Each Record is linked to a single DataPool.
Each Value is linked to one Field.
Also, all the Name columns have unique values.
Now, here's the problem:
I need to query evey value form the Values table based on the following columns:
The Name of the Field linked to the Value
The Name of the DataPool linked the Record linked to the Value
The Name of the Form linked to that DataPool
The 3 columns above must be equal to the 3 received parameters in the stored procedure.
Here's what I got so far:
CREATE PROCEDURE [GetValues]
#FieldName NVARCHAR(50),
#FormName NVARCHAR(50),
#PoolName NVARCHAR(50)
AS SELECT Value FROM [Values]
JOIN [Fields]
ON [Fields].FieldID = [Values].FieldID
WHERE [Fields].FieldName = #FieldName
How can I filter the rows of the Values table by the PoolName column? The DataPools table isn't directly related to the Values table, but it's still related to the Records table which is directly related to the Values table. Any ideas on how to do that?

Answer 1

I feel like I am missing something in your question. If this solution is not addressing the problem, please let me know where it is missing the issue.
SELECT
Values.Value
FROM
Values INNER JOIN Fields ON
Values.FieldId = Fields.FieldId
INNER JOIN FormFields ON
Fields.FieldId = FormFields.FieldId
INNER JOIN Forms ON
FormFields.FormId = Forms.FormId
INNER JOIN DataPools ON
Forms.FormId = DataPools.FormId
WHERE
Fields.FieldName = #FieldName
AND
Forms.FormName = #FormName
AND
DataPools.PoolName = #PoolName;

Answer 2

if i understand what your needing this should work just fine.
select * from
values v
join records r
on v.recordid = r.recordid
join datapool dp
on r.poolid = dp.poolid
join forms f
on r.formid = f.formid
join fields fi
on v.fieldid = fi.fieldid
where
fi.FieldName = #FieldName
AND
f.FormName = #FormName
AND
dp.PoolName = #PoolName;