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Which Transact-SQL query should you use?

You administer a Microsoft SQL Server 2012 databasethat includes a table named Products. The Products
table has columns named Productld, 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?

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A.
WITH CTEDupRecords
AS
(
SELECT MAX(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

B.
WITH CTEDupRecords
AS
(
SELECT MAX(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

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

D.
WITH CTEDupRecords
AS
(
SELECT MAX(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

Explanation:
Verified answer as correct.

6 Comments on “Which Transact-SQL query should you use?

  1. Mr.Awesome says:

    How is it B??

    “FROM Products p
    JOIN CTEDupRecords cte ON
    cte.ProductName = p.ProductName ” does not makes sense at all

    it should be “DELETE p
    FROM Products p
    JOIN CTEDupRecords cte ON
    p.ProductName = cte.ProductName ” which leaves A to be the correct answer.

    in any place you look how to do a join the table after the “FROM” Always comes before the table after the join.




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  2. dusg84 says:

    i think that b is the correct answer not a because the subjet said “remove all duplicate of the product tabla based on the product name column” then AND cte.crateddatetime > p.createddatetime is the key




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