![]() ![]() Databases store data for later retrieval. Create a pull request to the class repo. MySQL HOME MySQL Intro MySQL RDBMS MySQL SQL MySQL SQL MySQL SELECT MySQL WHERE MySQL AND, OR, NOT MySQL ORDER BY MySQL INSERT INTO MySQL NULL Values MySQL UPDATE MySQL DELETE MySQL LIMIT MySQL MIN and MAX MySQL COUNT, AVG, SUM MySQL LIKE MySQL Wildcards MySQL IN MySQL BETWEEN MySQL Aliases MySQL Joins MySQL INNER JOIN MySQL LEFT JOIN MySQL. SELECT QUERY is used to fetch the data from the MySQL database.solution.sql that contains all your MySQL queries.Also order your results based on TOTAL from high to low. Note that the authors who have sold 0 titles should also appear in your output (ideally display 0 instead of NULL as the TOTAL). Now modify your solution in Challenge 3 so that the output will display all 23 authors instead of the top 3. Only output the top 3 best selling authors.Ĭhallenge 4 - Best Selling Authors Ranking.Your output should be ordered based on TOTAL from high to low. ![]() TOTAL - total number of titles sold from this author.Your output should have the following columns:.Who are the top 3 authors who have sold the highest number of titles? Write a query to find out. These features will be formally discussed in the Temp Tables and Subqueries lesson. Refer to the references and learn by yourself. Also check out MySQL Group By because you will count the rows of different groups of data. You can calculate the total (and from that the desired percentage) by using a subquery in the FROM clause: SELECT Name, SUM (Value) AS 'SUM (VALUE)', SUM (Value) / totals.total AS ' of Total' FROM table1, ( SELECT Name, SUM (Value) AS total FROM table1 GROUP BY Name ) AS totals WHERE table1.Name totals.Name AND Year BETWEEN 2000 AND. Hint: In order to count the number of titles published by an author, you need to use MySQL COUNT. The sum number should be the same as the total number of records in Table titleauthor. ![]() To check if your output is correct, sum up the TITLE COUNT column. Your output should look something like below: Challenge 2 - Who Have Published How Many At Where?Įlevating from your solution in Challenge 1, query how many titles each author has published at each publisher. In general, parentheses can be ignored in join expressions containing only inner join operations. INNER JOIN is used with an ON clause, CROSS JOIN is used otherwise. In standard SQL, they are not equivalent. If your query is correct, the total rows in your output should be the same as the total number of records in Table titleauthor. In MySQL, JOIN, CROSS JOIN, and INNER JOIN are syntactic equivalents (they can replace each other). Note: the screenshot above is not the complete output. Your output will look something like below:
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