project for resolving tasks from Database advanced module in scope of preparing to assesment.
- Tunning and performance optimization
- Query Processing
- SQL for Data Scientists
task.sql contains the following queries:
- all primary skills that contain more than one word (please note that both ‘-‘ and ‘ ’ could be used as a separator)
- all students who do not have a second name (it is absent or consists of only one letter/letter with a dot)
- number of students passed exams for each subject and order result by a number of student descending
- the number of students with the same exam marks for each subject
- students who passed at least two exams for different subjects
- students who passed at least two exams for the same subject
- all subjects which exams passed only students with the same primary skills
- all subjects which exams passed only students with the different primary skills. It means that all students passed the exam for the one subject must have different primary skill
- students who do not pass any exam using each of the following operator: 'outer join', 'not in', 'any'
- all students whose average mark is bigger than the overall average mark
- the top 5 students who passed their last exam better than average students
- the biggest mark for each student and add text description for the mark (use COALESCE and WHEN operators)
- the number of all marks for each mark type (‘BAD’, ‘AVERAGE’,…)