Question

I have table OrderLines(OrderID int, LineIndex int, ) and table valued parameter of the same structure defining new order lines for one order.

So if I had the following OrderLines

1000   1   bread
1000   2   milk
1001   1   oil
1001   2   yogurt
1002   1   beef
1002   2   pork

and the following TVP

1001   1   yogurt

I want to get the following OrderLines

1000   1   bread
1000   2   milk
1001   1   yogurt
1002   1   beef
1002   2   pork

I.e. touch rows only for one Order.

So I wrote my query like this

MERGE
    [OrderLines] AS [Target]
USING
(
    SELECT
        [OrderID], [LineIndex], [Data]
    FROM
        @OrderLines
)
AS [Source] ([OrderID], [LineIndex], [Data])
ON ([Target].[OrderID] = [Source].[OrderID]) AND ([Target].[LineIndex] = [Source].[LineIndex])
WHEN MATCHED THEN
    UPDATE
    SET
        [Target].[Data] = [Source].[Data]
WHEN NOT MATCHED BY TARGET THEN
    INSERT
        ([OrderID], [LineIndex], [Data])
    VALUES
        ([Source].[OrderID], [Source].[LineIndex], [Source].[Data])
WHEN NOT MATCHED BY SOURCE THEN
    DELETE;

and it deletes all other (not mentioned) OrderLines for other Orders.

I tried

WHEN NOT MATCHED BY SOURCE AND ([Target].[OrderID] = [Source].[OrderID]) THEN

but got a syntactic error.

How should I rewrite my query?

Answer 1

Just use the relevant subset of OrderLines as the target:

WITH AffectedOrderLines AS (
    SELECT *
    FROM OrderLines
    WHERE OrderID IN (SELECT OrderID FROM @OrderLines)
)
MERGE
    AffectedOrderLines AS [Target]
USING
(
    SELECT
        [OrderID], [LineIndex], [Data]
    FROM
        @OrderLines
)
AS [Source] ([OrderID], [LineIndex], [Data])
ON ([Target].[OrderID] = [Source].[OrderID]) AND ([Target].[LineIndex] = [Source].[LineIndex])
WHEN MATCHED THEN
    UPDATE
    SET
        [Target].[Data] = [Source].[Data]
WHEN NOT MATCHED BY TARGET THEN
    INSERT
        ([OrderID], [LineIndex], [Data])
    VALUES
        ([Source].[OrderID], [Source].[LineIndex], [Source].[Data])
WHEN NOT MATCHED BY SOURCE THEN
    DELETE;

And here’s a SQL Fiddle to test.