Author Question: Which type of index is commonly used in data warehousing environments? A) Joint index B) ... (Read 101 times)

tfester

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Which type of index is commonly used in data warehousing environments?
 
  A) Joint index
  B) Bit-mapped index
  C) Secondary index
  D) Tri-dex

Question 2

Discuss when to use the GROUP BY clause.
 
  What will be an ideal response?


cloud

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Answer to Question 1

B

Answer to Question 2

The GROUP BY clause is useful when you have a set of values for one column (such as a salesperson ID) and you would like to then calculate something like total sales for each salesperson. Rather than having to use the sum function with one salesperson's ID in the WHERE clause (and run multiple queries) you can use the GROUP BY to get the same results in one query.



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cloud

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