Databases / SQL
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To find the third highest salary in a table, you can use a SQL query. For example, given the following table:
| ID | Name | Salary |
|---- |-------|--------|
| 1 | John | 1000 |
| 2 | Jane | 2000 |
| 3 | Joe | 3000 |
| 4 | Sarah | 4000 |
| 5 | Dave | 5000 |
The third highest salary would be Joe's, with a salary of 3000.
About this solution: The candidate's solution is correct and uses the optimal approach to return the 3rd highest salary.
This technical problem involves writing a SQL query to find the average salary of employees by department. The example input table includes columns for department, first name, last name, and salary. The expected output is a table with columns for department and average salary.
About this solution: This solution is complete and solves the problem. The approach is straightforward and easy to follow.
The problem is to write a query to return the average price of all products in an unnormalized database table. The table includes the attributes productID, productName, productDescription, and productPrice.
About this solution: The candidate's solution is correct and demonstrates a level of completeness. The candidate's approach is straightforward and solves the problem efficiently.
Given a database with two tables, Employees and Departments, this SQL query will find the names of all employees who work in the Sales department.
About this solution: The candidate's solution is complete and solves the problem. The approach is general and could be applied to other similar problems.
This technical problem deals with designing a social network database schema that includes posts, comments, and likes. The input is a set of CREATE TABLE statements for the three tables, and the output is sample data for those tables.
About this solution: The solution is optimal because it uses foreign keys to ensure data integrity.
To find the customer with the highest balance, you can use a simple SQL query as follows:
SELECT customer_id, name, balance
FROM customers
ORDER BY balance DESC
LIMIT 1
About this solution: The solution above is optimal because it uses the ORDER BY and LIMIT clauses to sort the table by balance in descending order and then return the first row.
Write a stored procedure that returns the name and salary of the highest paid employee from a table of data.
About this solution: The candidate's solution is correct and demonstrates a good understanding of how to solve the problem. The approach is efficient and uses a subquery to find the maximum salary, which is then used to return the name and salary of the employee with that salary.
Write a SQL query to find all pairs of distinct values in two columns.
About this solution: The solution above is optimal because it uses the DISTINCT keyword to remove duplicates.