Caple SQL Joins

I didn't look at the solutions, and came up with SQL statements that varied from two of the published results (questions 7 and 9). My SQL is from my knowledge of standard SQL more than any study of PostgreSQL with the exception of question 10, which I researched through various sources: DISTINCT ON seems to be pure dialect.

Question 7: My sense is that some judgement could be made in the logic (e.g. question 7 "within the last 7 days" could be interpreted as the last 7 days of the data store, the most recent 7 days ending today but not extending into the future, etc.)

Question 9: Look at the raw data as well as results from my ungrouped query statement - I believe that George does indeed have 4 posts that he has not personally commented on. The official results report only 3 posts.

Lastly, check out my 'bonus' query for word count instead of character count for question 3. Can't take a whole lot of credit for cut and paste from web research, though.