Author Question: Which type of index is commonly used in data warehousing environments? A) Joint index B) ... (Read 114 times)

tfester

  • Hero Member
  • *****
  • Posts: 534
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

  • Sr. Member
  • ****
  • Posts: 343
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.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question

cloud

  • Sr. Member
  • ****
  • Posts: 343

 

Did you know?

IgA antibodies protect body surfaces exposed to outside foreign substances. IgG antibodies are found in all body fluids. IgM antibodies are the first type of antibody made in response to an infection. IgE antibody levels are often high in people with allergies. IgD antibodies are found in tissues lining the abdomen and chest.

Did you know?

Acetaminophen (Tylenol) in overdose can seriously damage the liver. It should never be taken by people who use alcohol heavily; it can result in severe liver damage and even a condition requiring a liver transplant.

Did you know?

Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.

Did you know?

Bisphosphonates were first developed in the nineteenth century. They were first investigated for use in disorders of bone metabolism in the 1960s. They are now used clinically for the treatment of osteoporosis, Paget's disease, bone metastasis, multiple myeloma, and other conditions that feature bone fragility.

Did you know?

Every 10 seconds, a person in the United States goes to the emergency room complaining of head pain. About 1.2 million visits are for acute migraine attacks.

For a complete list of videos, visit our video library