Create printable tests and worksheets from Databases questions.

The Databases questions below are in the following grade level(s):

• Write a query to list the the colors in the table Colors. The output of the query should look like this:
  
  

  unique colors
  Blue
  Green
  Orange
  Red

  • 
    SELECT DISTINCT 
      C.color
      FROM
        Colors C
      ORDER BY
        color;
    

• Which type of sub query can be evaluated independently?
  1. correlated
  2. uncorrelated

• Write a query to count the number of times each color appears in the table Colors. Your output should look like this:
  
  

  color	count
  Blue	2
  Green	1
  Orange	1
  Red	3

  • 
    SELECT 
      C.color, 
      count(*) AS count
      FROM
        Colors C
      GROUP BY
        color
      ORDER BY
        color;