Tag: CTE

  • An Example of Using LEAD and LAG Functions from SQL Server 2012

    I recently encountered a technical interview question and it was something like this: A company has its door access logging system and the company policy dictates that every employee’s card-in/card-out records shall reflect his/her true presence in or absence from office. But somehow, some employees skip cardings or tailgate behind others. Therefore, the logging system…

  • Remove Full Duplicates by Using row_number() Function and Common Table Expression

    This blog article is inspired by another very informative one which explains really well the meaning of the new row_number() function introduced since SQL2005. Since the original article did not give a full answer to how to delete multiple fully duplicated rows in a table, I am putting my code here for the test. The good…