Merge sql with date condition - sql

Question

I have create merge stored procedures as below, what i am trying to achieve is the following scenario:
Merge the new record if ProductTRN is not exist in ProductList table (complete)
Only Update the ProductList record in where the PU.CreateDate is bigger than CreateDate of target table which is ProductList (Not Complete)
Please advise me how I can achieve the second scenario above, thank you
CREATE PROCEDURE [dbo].[usp_ProductList_Merge]
AS
BEGIN
DECLARE #retValue INT
BEGIN TRY
IF OBJECT_ID('ProductList') IS NOT NULL
BEGIN
BEGIN TRANSACTION MergeConsumerTable
SET NOCOUNT ON;
MERGE dbo.ProductList AS target
USING
( SELECT
PU.ProductTRN,
PU.ProductName,
PU.ProductDescription,
PU.CreateDate
FROM dbo.TmpProductList PU
WHERE PU.ProductTRN = ProductTRN
) AS source (
ProductTRN,
ProductName,
ProductDescription
CreateDate)
ON ( (target.ProductTRN) = LOWER(source.ProductTRN)
)
WHEN MATCHED
THEN
UPDATE SET
ProductTRN= source.ProductTRN
WHEN NOT MATCHED
THEN
INSERT (
ProductTRN,
ProductName,
ProductDescription,
CreateDate
) VALUES
(
source.ProductTRN,
source.ProductName,
source.ProductDescription,
source.CreateDate,
);
DELETE PU
FROM dbo.TmpProductList PU
COMMIT TRANSACTION MergeProductListTable
SET #retValue = 1
SELECT #retValue
END
ELSE
BEGIN
SET #retValue = -1
SELECT #retValue
END
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION MergeProductListTable
DECLARE #ErrorMsg VARCHAR(MAX);
DECLARE #ErrorSeverity INT;
DECLARE #ErrorState INT;
SET #ErrorMsg = ERROR_MESSAGE();
SET #ErrorSeverity = ERROR_SEVERITY();
SET #ErrorState = ERROR_STATE();
SET #retValue = 0
SELECT #retValue
-- SELECT 0 AS isSuccess
END CATCH
END

Answer 1

WITH Source AS (
SELECT ProductTRN
,ProductName
,ProductDescription
,CreateDate
FROM dbo.TmpProductList
)
MERGE ProductList AS Target
USING Source
ON Target.ProductTRN = Source.ProductTRN
WHEN MATCHED
AND Source.CreatedDate > Target.CreatedDate
THEN UPDATE SET
ProductName = Source.ProductName
,ProductDescription = Source.ProductDescription
,CreateDate = Source.CreatedDate
WHEN NOT MATCHED BY TARGET
THEN INSERT (
ProductTRN
,ProductName
,ProductDescription
,CreateDate
)
VALUES (
Source.ProductTRN
,Source.ProductName
,Source.ProductDescription
,Source.CreatedDate
)