Multiple Table Insert with Merge? - sql

Question

I am trying to insert some rows in a parent/child relationship. How does one accomplish this in SQL?
This would be the base query I'd use to find the info I would be inserting:
SELECT * FROM parentTable p
INNER JOIN childTable c
ON p.ID = c.ParentTableID
WHERE p.PlanID = 123456
What needs to happen is that I insert the ParentTable row first which is really just a copy of the matched row but with a new PlanID and Created Date. Then I take that ParentTable ID from the inserted row and use that for the same process but for the Child Table.
So I need to do in .Net speak at least is where I loop through all parentTable matches and for each match create 1 childTable row.
I was trying to use MERGE and the OUTPUT clause but it seems like I'm maybe using a square peg for a round hole. Would I be better off using a CURSOR of some sorts?
So this is what I have so far based on the answer below. Unfortunately it isn't grabbing the SCOPE_IDENTITY()...is there a trick to it? Because that is returning NULL I get FK errors on the inserts.
USE MemberCenteredPlan
DECLARE #NewPlanID BIGINT;--49727690
DECLARE #OldPlanID BIGINT;--49725211
DECLARE #NewSWReAssID BIGINT;
SET #NewPlanID = 49727690
SET #OldPlanID = 49725211
BEGIN
INSERT INTO tblSocialWorkerReAssessment
SELECT
#NewPlanID
,[Discussed]
,Discussion
,NULL
,NULL
,NULL
,CreatedBy
,GETDATE()
,NULL
,NULL
FROM tblSocialWorkerReAssessment
WHERE PlanID = #OldPlanID
SELECT #NewSWReAssID = SCOPE_IDENTITY();
INSERT INTO tblPlanDomain
SELECT
#NewPlanID
,[DomainTypeID]
,[MemberOutcomes]
,[MemberPreferences]
,[DomainDate]
,[Steps]
,[ClinicalFunctionalConcerns]
,[ReportWageES]
,[ReportWageSSA]
,#NewSWReAssID
,[CreatedBy]
,GETDATE()
,NULL
,NULL
,NEWID()
FROM tblPlanDomain
WHERE planID = #OldPlanID
END

Answer 1

You don't need MERGE and you definitely don't need cursors. And an INSERT (or a MERGE) can only ever affect one table at a time, so you'll need to perform multiple statements anyway. If you are only ever dealing with one plan at a time, you can do this:
DECLARE #NewPlanID INT;
INSERT dbo.ParentTable(cols...)
SELECT cols...
FROM dbo.ParentTable WHERE PlanID = 123456;
SELECT #NewPlanID = SCOPE_IDENTITY();
INSERT dbo.ChildTable(ParentTableID, cols...)
SELECT #NewPlanID, cols...
FROM dbo.ChildTable WHERE PlanID = 123456;
If you need to reference multiple new plans, it gets a little more complicated, and in that case you would need to use MERGE (at the present time, INSERT's composable DML is a little on the light side - you can't reference the source table in the OUTPUT clause).
DECLARE #p TABLE(OldPlanID INT, NewPlanID INT);
MERGE dbo.ParentTable WITH (HOLDLOCK)
USING
(
SELECT ID, cols... FROM dbo.ParentTable
WHERE ID IN (123456, 234567)
) AS src ON src.ID IS NULL
WHEN NOT MATCHED THEN INSERT(cols...)
VALUES(src.cols...)
OUTPUT src.ID, inserted.ID INTO #p;
INSERT dbo.ChildTable(ParentTableID, cols...)
SELECT p.NewPlanID, t.cols...
FROM dbo.ChildTable AS t
INNER JOIN #p AS p
ON t.ParentTableID = p.OldPlanID;
However, you should be very wary about this... I link to several issues and unresolved bugs with MERGE in this answer over on dba.SE. I've also posted a cautionary tip here and several others agree.

Answer 2

I think this is what you're after.
Use Northwind
GO
SET NOCOUNT ON
IF OBJECT_ID('tempdb..#OrderAuditHolder') IS NOT NULL
begin
drop table #OrderAuditHolder
end
CREATE TABLE #OrderAuditHolder
(
[OriginalOrderID] [int] NOT NULL,
[NewOrderID] [int] NOT NULL,
[CustomerID] [nchar](5) NULL,
[EmployeeID] [int] NULL,
[OrderDate] [datetime] NULL,
[RequiredDate] [datetime] NULL,
[ShippedDate] [datetime] NULL,
[ShipVia] [int] NULL,
[Freight] [money] NULL,
[ShipName] [nvarchar](40) NULL,
[ShipAddress] [nvarchar](60) NULL,
[ShipCity] [nvarchar](15) NULL,
[ShipRegion] [nvarchar](15) NULL,
[ShipPostalCode] [nvarchar](10) NULL,
[ShipCountry] [nvarchar](15) NULL,
)
declare #ExampleOrderID int
select #ExampleOrderID = (select top 1 OrderID from dbo.Orders ords where exists (select null from dbo.[Order Details] innerOD where innerOD.OrderID = ords.OrderID ) )
print '/#ExampleOrderID/'
print #ExampleOrderID
print ''
insert into dbo.Orders (CustomerID,EmployeeID,OrderDate,RequiredDate,ShippedDate,ShipVia,Freight,ShipName,ShipAddress,ShipCity,ShipRegion,ShipPostalCode,ShipCountry)
output #ExampleOrderID , inserted.OrderID,inserted.CustomerID,inserted.EmployeeID,inserted.OrderDate,inserted.RequiredDate,inserted.ShippedDate,inserted.ShipVia,inserted.Freight,inserted.ShipName,inserted.ShipAddress,inserted.ShipCity,inserted.ShipRegion,inserted.ShipPostalCode,inserted.ShipCountry
into #OrderAuditHolder
Select
CustomerID,EmployeeID,OrderDate,RequiredDate,ShippedDate,ShipVia,Freight,ShipName,ShipAddress,ShipCity,ShipRegion,ShipPostalCode,ShipCountry
from dbo.Orders where OrderID = #ExampleOrderID
print '/#OrderAuditHolder/'
Select * from #OrderAuditHolder
print ''
Insert into dbo.[Order Details] ( OrderID , ProductID , UnitPrice , Quantity , Discount )
Select
holder.NewOrderID , od.ProductID , od.UnitPrice , od.Quantity , od.Discount
from #OrderAuditHolder holder
join dbo.[Order Details] od on holder.OriginalOrderID = od.OrderID
/* Note, the "join" is on the OriginalOrderID, but the inserted value is the NewOrderID */
/* below is not needed, but shows results */
declare #MaxOrderID int
select #MaxOrderID = (select MAX(OrderID) from dbo.Orders ords where exists (select null from dbo.[Order Details] innerOD where innerOD.OrderID = ords.OrderID ) )
select * from dbo.[Order Details] where OrderID = #MaxOrderID order by OrderID desc
/**/
IF OBJECT_ID('tempdb..#OrderAuditHolder') IS NOT NULL
begin
drop table #OrderAuditHolder
end
SET NOCOUNT OFF