How can I select records from MSSQL table with multiple SET dependencies?

Question

My table structure/data is this

Itemid    RechTyp PstNr  InvoicNr   

1          M       200   Null
2          B       200   84684
3          B       300   84684
4          B       400   84684
5          M       500   Null
6          B       500   84685
7          B       600   84685
8          B       700   84685 

The column ItemID is unique key. The column PstNr is reference for ItemID 1 & 2 While InvoiceNumber is unique reference for ItemID 2,3 & 4. For every set. The first M and B record is unified by PstNr.

I need a query that can select these 4 records. Bearing in mind that the table contains more than 10,000 records with this sets of records. I am thinking of using cet & Partition functions but I am still working on the query.

My Expected result is: See table below The Table MyTransaction , has a status row that is updated for every select statement, hence selecting based on itemID will not work. Becasue I have no gurantee on how the data are inserted. Its possible that ItemId 3 will be in the last row.

RechTyp   PstNr    InvioceNr
M       200   Null
B       200   84684
B       300   84684
B       400   84684

Answer 1

This could work well with a low-size table, but may have performance issues in a big records table:

DECLARE @TEMP TABLE (Itemid INT, RechTyp NVARCHAR(1), PstNr INT, InvoicNr INT NULL)
INSERT INTO @TEMP VALUES
(1,'M',200,   Null),
(2,'B',200,   84684),
(3,'B',300,   84684),
(4,'B',400,   84684),
(5,'M',500,   Null),
(6,'B',500,   84685),
(7,'B',600,   84685),
(8,'B',700,   84685)

DECLARE @INVOICE INT = 84684

SELECT *
FROM @TEMP
WHERE InvoicNr = @INVOICE
OR PstNr IN (
            SELECT PstNr
            FROM @TEMP
            WHERE InvoicNr = @INVOICE)

Output:

Itemid  RechTyp PstNr   InvoicNr
1   M   200 NULL
2   B   200 84684
3   B   300 84684
4   B   400 84684

Answer 2

Assuming I understand the question, you want to get all the records associated with a specific invoice number, and the problem is that one of these records doesn't have a value in it's InvoiceNr column, but you can identify it using the PstNr column.

I think this should get you your desired results:

;WITH CTE AS 
(
    SELECT RechTyp, PstNr, InvioceNr
    FROM Table
    WHERE InvioceNr = @InvioceNr
)

SELECT RechTyp, PstNr, InvioceNr
FROM CTE

UNION ALL

SELECT RechTyp, PstNr, InvioceNr
FROM Table
WHERE PstNr IN(SELECT PstNr FROM CTE)

ORDER BY PstNr, InvioceNr

Answer 3

This is the answer that work for me. I not a fan of union and join they are more resource intensive.

;With cte_get_invoice (ItemID ,RechTyp, InvoicNr, PstNr ,rownumber)
AS
(
SELECT ItemID ,RechTyp, InvoicNr, PstNr, row_number()over(partition by PstNr
                 ORDER BY RechTyp, InvoicNr, PstNr) 
                as rank from  TransactionTable
)

 select  RechTyp, InvoicNr, PstNr FROM TransactionTable
 where PstNr = (select top(1) PstNr from cte_get_invoice where rownumber  > 1 )
 or InvoicNr = (select top(1) InvoicNr from cte_get_invoice where rownumber  > 1 )