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Given a table salary, such as the one below, that has m=male and f=female values. Swap all f and m values (i.e., change all f values to m and vice ver 阅读全文
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Write a SQL query to get the second highest salary from the Employee table. For example, given the above Employee table, the query should return 200 a 阅读全文
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There is a table courses with columns: student and class Please list out all classes which have more than or equal to 5 students. For example, the tab 阅读全文
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Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything 阅读全文
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The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. Given the Em 阅读全文
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Write a SQL query to find all duplicate emails in a table named Person. For example, your query should return the following for the above table: Note: 阅读全文
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Table: Person Table: Address Write a SQL query for a report that provides the following information for each person in the Person table, regardless if 阅读全文
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X city opened a new cinema, many people would like to go to this cinema. The cinema also gives out a poster indicating the movies’ ratings and descrip 阅读全文
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There is a table World A country is big if it has an area of bigger than 3 million square km or a population of more than 25 million. Write a SQL solu 阅读全文
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You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality c 阅读全文