How to do Multiple Joins with Merge Into? - sql-server

Question

I have these 3 tables
Company
id
Branch
id
Items
id
StockNumber
Company can have many branches and a branch can have many items.
Now I got to write a query that will either insert or update an item depending on conditions.
Some items can only appear once in the company and some items can appear in each branch.
The problem for me is the ones that can only appear once in the company. I think I am going to need to basically join all these tables together and do a check but I don't know how to do this join in a "Merge Into Sp"
I made a table type that looks like this
CREATE TYPE ItemTableType AS TABLE
(
BranchId INT,
CompanyId INT
Description nvarchar(Max),
StockNumber: INT
);
In my code I can pass the companyId into my tabletype
CREATE PROCEDURE dbo.Usp_upsert #Source ItemTableType readonly
AS
MERGE INTO items AS Target
using #Source AS Source
ON
// need to somehow look at the companyId so I can then find the right record reguardlesss of which branch it sits in.
Targert.CompanyId = source.CompanyId // can't do this just like this as Item doesn not have reference to company table.
Target.StockNumber = source.StockNumber
WHEN matched THEN
// update
WHEN NOT matched BY target THEN
// insert
Edit
Sample Data
Company
Id Name
1 'A'
2 'B'
Branch
Id name CompanyId
1 'A.1' 1
2 'A.2' 1
3 'B.1' 2
4 'B.2' 3
Item
Id Name StockNumber BranchId
1 Wrench 12345 1
2 Wrench 12345 3
3 Hammer 484814 2
4 Hammer 85285825 4
Now a bulk data is going to be sent into this SP via C# code and looks something like this
DataTable myTable = ...;
// Define the INSERT-SELECT statement.
string sqlInsert = "dbo.usp_InsertTvp"
// Configure the command and parameter.
SqlCommand mergeCommand = new SqlCommand(sqlInsert, connection);
mergeCommand.CommandType = CommandType.StoredProcedure;
SqlParameter tvpParam = mergeCommand.Parameters.AddWithValue("#Source", myTable);
tvpParam.SqlDbType = SqlDbType.Structured;
tvpParam.TypeName = "dbo.SourceTableType";
// Execute the command.
insertCommand.ExecuteNonQuery();
Now say when an import of records come in and the data looks like this
Wrench (Name), 12345 (StockNumber), 2 (BranchId..they are switching the branch of this item to another branch)
If I would just send this in then if I used BranchId + Stocknumber nothing would be updated and a new record would be inserted what would be wrong as now 2 branches have the same item(based on stockNumber)
If I would just use StockNumber then these 2 records would be updated.
1 Wrench 12345 1
2 Wrench 12345 3
Which is wrong as these records are from 2 different companies. Thus I need to also use the companyId, thus I need to also check the companyId.
EDIT (from comments):
I think I have to do Target Dot something. This is what I came up with so far:
MERGE INTO Items AS Target
using #Source AS Source
ON Source.CompanyID=(
SELECT TOP 1 Companies.Id
FROM Branches
INNER JOIN Companies
ON Branches.CompanyId = Companies.Id
INNER JOIN InventoryItems
ON Branches.Id = Target.BranchId
where Companies.Id = Source.CompanyId
and StockNumber = Source.StockNumber
)

Answer 1

The description of what you need to do is too vague for me to be specific, but you can simply do a query with JOINs as your source. I like to put it in a CTE to make it pretty like so:
WITH cte AS (SELECT query with JOINS)
MERGE INTO items AS Target
using cte AS Source
ON
EDIT: To also do a JOIN on the Target (items) you need to do it in the ON conditions:
WITH cte AS (SELECT query with JOINS)
MERGE INTO items AS Target
using cte AS Source
ON Source.CompanyID=(
SELECT TOP 1 CompanyId
FROM TableWithCompanyId
JOIN Target
ON JoinCondition=true
)...
I know yours involves two tables to get from items to company, but the example above shows you the technique that I believe you are missing.
EDIT 2, based on latest attempt:
Try it this way:
MERGE INTO Items AS Target
using #Source AS Source
ON Source.CompanyID=(
SELECT TOP 1 Companies.Id
FROM Branches
INNER JOIN Companies
ON Branches.CompanyId = Companies.Id
WHERE Branches.Id = Target.BranchId
)
and Target.StockNumber = Source.StockNumber