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2:again with the column names they should be singular rather than plural, for example StudentCourse not StudentCourses, this will suggest multiplicity and be confusing for the user same should be said for spaces between words and the use of special characters, these too are bad practices.

3: databases without proper documentation for users are also bad practice, so make sure to give ER schemas so users could follow the integrity of data.

I need help on my database homework . I need to write SQL Statements i am not to sure how to do it

SQL Group By
A sql-6-9.sql file has been opened for you.

Write each of the following tasks as a SQL statement in a new line (remember that you can source the file to compare the output reference):

Use the e_store database
Join the products and the reviews tables that would output this:
----+------------+-----------+
| id | name | avg_stars |
+----+------------+-----------+
| 2 | Smartphone | 2.3333 |
| 3 | PC | 3.0000 |
+----+------------+-----------+
2 rows in set (0.01 sec)

Use the e_store database
Get the average rating of product_id 4. Alias the average result as: avg_rating.
The result should look like this:
+----+------------+
| id | avg_rating |
+----+------------+
| 4 | 3.5000 |
+----+------------+
1 row in set (0.08 sec)

Entities are

What are 3 good practices of creating databases in SQL?