This course has really helped with optimizing queries that I work with everyday, enhancing my understanding of RDBMS, joins, analyzing and structuring exactly what you need and yielding those results.
Well it was a short course, the assignments are a little bit repetitive (mostly in the last). The course reviews every 'practical' aspects of SQL, how to assemble the bricks while writing queries,...
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The lectures and weekly coursework were fine -- although a bit too easy. The emphasis on certain aspects, such as formatting/commenting, and some comments on joins were on point. Sadie has a soothing voice and good pace, although the content somewhat drags at places. Not her fault as a presenter, the videos were just going too slow imo. There were a few typos in the lecture slides, one of which was quite confusing (I have reported them separately).
Unfortunately what really stood out in a negative way was the peer-graded assignment. This *really* needs to be rewritten. Specific problems:
Questions 5 to 7 could be answered in two different ways: one, which is the "easier" one and the one that the marking guide forced us to accept, is to read off review_count from the Business table (and descend-order it). The first few results this way are
| city | reviews |
| Las Vegas | 82854 |
| Phoenix | 34503 |
| Toronto | 24113 |
| Scottsdale | 20614 |
| Charlotte | 12523 |
| Henderson | 10871 |
The problem with this is that the data set we're working on is a SUBSET of the full Yelp set. This means that the Business.review_count column (which was presumably added there in a redundant, denormalized way, in order to speed up queries) contains much higher counts than the ones that would be obtained by actually joining the Business and Review tables (on business id) and grouping by city. Here are the first few results of this approach, which imo is the correct one:
| city | reviews |
| Las Vegas | 193 |
| Phoenix | 65 |
| Toronto | 51 |
| Scottsdale | 37 |
| Henderson | 30 |
| Tempe | 28 |
I would be totally ok if the marking guide gave us the choice to accept both methods, but that wasn't the case.
Q1 of Part2 was badly worded and unclear. It asks us to "pick a city AND a category" but then to group the businesses (by star rating) "in that city OR category". What exactly does that mean? Lump together all businesses from eg Phoenix (regardless of category) with the eg Restaurants businesses (regardless of city)? What's the rationale behind this? Or was it meant to read "in that city AND category" (meaning that we would only consider restaurants from Phoenix)?
Also, Q1.iii is both random and vague: why location? What do you mean by location (zip code? longitude/latitude?). This ties to the above ambiguity (X=AND vs X=OR in "in that city X category").
By Alexander B•
Overall rating: The course itself was really good for beginners. I really like SQL
You get a lot of information and it has a clear structure.
There are nice examples and you can train enough.
The rate of speaking of the teacher was perfect for me.
A very good thing was that the questions of the exam fit perfectly well to the information we were taught in the classes.
What i did not like is, that even though you get clear instructions how to write and structure your code, the teacher did not stick to the rules all the time or structured the code in a way, which was not mentioned before.
The reason why i only give 3 stars to this course is that the final assignment was the worst thing i ever experienced in a course. The instructions very totally unclear a lot of times and I had to search the discussion forum to find out what the questions are about. They could be interpreted in many different ways. Additionally, sometimes specific things were asked for like correlation, which is simply not possible if you take the question seriously. This would be a complicated formula, but the real intention of the question was to check it roughly by eye. But you can not tell what the intention is before you know the result and so it took me a lot of time to find out what the intention of several questions was. According to the discussion forum this problem is know for several years now. So enough time to fix it. Therefore i took two stars from the course.
By Jasmine B•
Coming from someone who has zero experience using SQL, I can only describe this course as okay. On one hand I was able to build somewhat of a foundation seeing that I had no information prior to this course, alternatively the presentation of material especially as we approached week 3 was subpar. Week 3 and 4 had material that was much more involved and complicated compared to the prior weeks. The lectures were not at all sufficient enough to get a good understanding of the material. I found I had to find clarity using online tools, posting multiple (frequently unanswered) questions in the forum, and searching through pages and pages of forum posts in hopes that someone would have the same question I did. Painstakingly going through the lecture transcript on a specific topic was generally the last resort. To briefly speak more about the lecture delivery, I found it distractingly rehearsed. It's as if the material wasn't reviewed before reading it word for word to the students. There were so many misreads and phrases that made zero sense and these mistakes were carried through even to the most difficult concepts where a succinct, clear, informative delivery is desperately needed. I honestly felt like I was floundering in week 3 and especially week 4. The peer assignment questions were unclear and seemed to be asking questions on material we haven't covered or haven't covered in depth enough to answer some of the questions.
By Bohdan Z•
In general, course was not bad as for me, but there are some problems. On my opinion, main problem is luck of practice. Teacher tell about everything but all you see is explaining idea and purposes of using some statement, then boom and whole code on your screen, and you just seat and don't interact with SQL while listening the lecture. It was easier for me, since I've already knew some basics from another course, but I would definitely struggle if this was my first course in SQL. Also, in the beginning some task seemed to be given earlier then material needed for them. And the last problem is the last assignment. It seemed interesting for me at the beginning, but in the middle I got stuck with questions, cause they was made with hope on knowledge of student and, as I found out later, one of them doesn't have a certain answer. The most challenging was the last task in the assignment but problem was again in understanding what is needed from you, not in difficulty of writing some SQL code. It would be better, if links on useful sources were given before last assignment, so people at least had idea what to do and get some additional knowledge at the same time. At the same time, course have structure and some practical tests, so that's why I give it 3 stars.
By RODRIGO T S•
I think there are many things that could be improved about this course. It feels a bit rushed when it comes to the videos, which could offer a bit more information. There are some concepts that I had some difficulty grasping because they weren't explored with sufficient depth. And also, there are some other aspects which do not appear in the course, but which I feel would be useful, such as perhaps how to use database management systems themselves to extract data to your computer, since in this course you only learn how to write queries, and not how to extract the information you've queried to your computer.
In addition, I think the database used for the final task is flawed, and this gives some strange results when performing it.
On a more positive note, I did actually learn a lot from te course, and I think the proramming tasks where really helpful, and actually kind of interesting, as you get the chance to play around with your queries and experiment with the results (despite the aforementioned flaw).