From: http://programmers.stackexchange.com/a/21024

Assuming the following basic  table structure
 - Documents (DocID, DocDate)
 - Keywords (KeyWordID, KeyWord)
 - DocumentKeywords (DocID,KeywordID)-- Write a query to return the following:
   - part 1: Documents with a DocDate after 4/1/1995
   - part 2: Documents that contain the keyword "Blue"
   - part 3: Documents that contain the either the keyword "Blue" or "Yellow"
   - part 4: Documents that contain the both the keywords "Blue" and "Yellow"

 NOTE: I used SQLite for this.
Merge branch 'document-keywords'