Author Question: Which type of index is commonly used in data warehousing environments? A) Joint index B) ... (Read 51 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?

People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.

Did you know?

Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.

Did you know?

The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.

Did you know?

Ether was used widely for surgeries but became less popular because of its flammability and its tendency to cause vomiting. In England, it was quickly replaced by chloroform, but this agent caused many deaths and lost popularity.

Did you know?

Malaria mortality rates are falling. Increased malaria prevention and control measures have greatly improved these rates. Since 2000, malaria mortality rates have fallen globally by 60% among all age groups, and by 65% among children under age 5.

For a complete list of videos, visit our video library