Practice Advanced Sql And Nosql For Data Science (19) - Advanced SQL and NoSQL for Data Science

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10 questions

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5 cards from this section. Quick, good the night before a test.
Exercise
6 questions · about 4 min · pass mark 70%. Hints available.
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Quiz
4 questions · about 3 min · pass mark 70%. Hints available.
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6 sample questions

Question 1.
Define a subquery and provide an example.
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Think about how filtering works within a query.
Question 2.
What does a CTE do?
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What do we call a temporary result set in SQL?
3Question 3.
What is the purpose of a subquery in SQL?
- To enhance data structure
- Improve performance
- Query within a query
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Consider how queries can be layered.
4Question 4.
True or False: CTEs are only used in nested queries.
- True
- False
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Think about the functionality of CTEs beyond nesting.
Question 5.
Create a SQL query using a subquery that finds the names of employees who have the highest salary within each department.
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You may need to consider aggregation and grouping functions.
Question 6.
Describe how you would use CTEs to find the total sales in each region using sales data.
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Remember the structure of a CTE and how to use the WITH clause.

6 more questions in this section. Enroll free to practise them all.