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Intermediate SQL
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Intermediate SQL

Intermediate SQL

1. Grouping
GROUP BY ClauseOrder of StatementsChallenge: Total Ride Time for Each Subway LineAverage Student's Grade ChallengeSearching for the Top Math Students ChallengeHAVING ClauseSeveral Aggregate Functions in the QueryMore Complex Filtering
2. Nested Subqueries
Nested QueriesChallenge: Non-tech Department EmployeesUsing Inner Subqueries in the FROM SectionChallenge: Employees With More Than Average SalaryUNION ClauseChallenge: Combining Table Results
3. Joining Tables
JOIN 2 TablesChallenge: Get Category By Product PriceChallenge: Get Minimum Price By CategoryChallenge: Get Product Amount By CategoryLEFT, RIGHT and INNER JOINsChallenge: Table JoinChallenge: FULL JOIN Usage
4. DDL and DML in SQL
CREATE and ConstraintsALTER and INSERT OperationsDROP and TRUNCATEUPDATE and DELETE

book
Several Aggregate Functions in the Query

The school now knows the last names of those students who received more than one grade for exams, and the administration has decided to calculate the average grade from multiple grades of these students, and that will be their final grade.

Uppgift

Swipe to start coding

You should retrieve the last names of students with more than one exam grade and also calculate the average grade from all their grades. In the response, you should have 2 columns: the first one is the student_surname, and the second one is the average_grade. Use AVG() and COUNT() aggregate functions in this task.

Also, sort the result by the student_surname column in the ascending order.

Brief Instructions

  • Retrieve the student_surname column and the average of the grade column using the AVG function.
  • Assign the alias average_grade to the second column.
  • Group the data by student_surname.
  • Use the HAVING clause to filter the results based on COUNT(grade) > 1.
  • Sort the results by student_surname.

Lösning

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Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 7
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book
Several Aggregate Functions in the Query

The school now knows the last names of those students who received more than one grade for exams, and the administration has decided to calculate the average grade from multiple grades of these students, and that will be their final grade.

Uppgift

Swipe to start coding

You should retrieve the last names of students with more than one exam grade and also calculate the average grade from all their grades. In the response, you should have 2 columns: the first one is the student_surname, and the second one is the average_grade. Use AVG() and COUNT() aggregate functions in this task.

Also, sort the result by the student_surname column in the ascending order.

Brief Instructions

  • Retrieve the student_surname column and the average of the grade column using the AVG function.
  • Assign the alias average_grade to the second column.
  • Group the data by student_surname.
  • Use the HAVING clause to filter the results based on COUNT(grade) > 1.
  • Sort the results by student_surname.

Lösning

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 1. Kapitel 7
Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Vi beklagar att något gick fel. Vad hände?
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