Câu 2: 70-461: MCSA Querying Microsoft SQL Server 2012/2014

You administer a Microsoft SQL Server database that includes a table named Products. The Products table has columns named ProductId, ProductName, andCreatedDateTime. The table contains a unique constraint on the combination of ProductName and CreatedDateTime. You need to modify the Products table to meet the following requirements: ✑ Remove all duplicates of the Products table based on the ProductName column. ✑ Retain only the newest Products row. Which Transact-SQL query should you use?

1. A. WITH CTEDupRecords AS ( SELECT MIN(CreatedDateTime) AS CreatedDateTime, ProductName FROM Products GROUP BY ProductName HAVING COUNT(*) > 1 ) DELETE p FROM Products p JOIN CTEDupRecords cte ON cte.ProductName = p.ProductName AND cte.CreatedDateTime > p.CreatedDateTime
2. B. WITH CTEDupRecords AS ( SELECT MIN(CreatedDateTime) AS CreatedDateTime, ProductName FROM Products GROUP BY ProductName HAVING COUNT(*) > 1 ) DELETE p FROM Products p JOIN CTEDupRecords cte ON p.ProductName = cte.ProductName AND p.CreatedDateTime > cte.CreatedDateTime — đáp án hiện tại
3. C. WITH CTEDupRecords AS ( SELECT MIN(CreatedDateTime) AS CreatedDateTime, ProductName FROM Products GROUP BY ProductName ) DELETE p FROM Products p JOIN CTEDupRecords cte ON p.ProductName = cte.ProductName
4. D. WITH CTEDupRecords AS ( SELECT MAX(CreatedDateTime) AS CreatedDateTime, ProductName FROM Products GROUP BY ProductName HAVING COUNT(*) > 1 ) DELETE Products FROM Products p