WISE OWL EXERCISES
- Simple Queries (4)
- Setting criteria using WHERE (5)
- Calculations (7)
- Calculations using dates (4)
- Basic joins (8)
- More exotic joins (2)
- Aggregation and grouping (8)
- Views (5)
- Subqueries (5)
- Stored procedures (5)
- Variables (8)
- Parameters and return values (11)
- Testing conditions (1)
- Looping (3)
- Scalar functions (6)
- Transactions (5)
- Creating tables (5)
- Temporary tables and table variables (9)
- Table-valued functions (6)
- Derived tables and CTEs (13)
- Dynamic SQL (4)
- Pivots (2)
- Triggers (2)
- Archived (70)
SQL | Aggregation and grouping exercise | Show the number of episodes written by each author
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If you haven't already done so, run the script in the above folder to generate the Doctor Who database.
The following diagram shows how the authors and episodes tables are related:
You're probably familiar with this by now!
Use this to show for each author:
- the number of episodes they wrote;
- their earliest episode date; and
- their latest episode date.
If you sort these so that the most prolific authors come first, here are the first few of the 25 rows you should see:
Those who know their Doctor Who won't be surprised at the two leaders.
Save this query as Blink was the best, then close it down.
select AuthorName, count(EpisodeNumber), EpisodeDate as [Earliest date], EpisodeDate as [Latest date] from
tblAuthor INNER JOIN tblEpisode ON tblAuthor.AuthorId=tblEpisode.AuthorId
group by AuthorName, EpisodeDate
order by [Earliest date] asc, [Latest date] desc
What is the problem with my code?