SQL Commands for: 1.) TOP-N query. Find the ssn, lname, and salary of the four highest paid employees. 2.) TOP-N query. Find the ssn, lname, and salary of the four lowest paid employees 3.) TOP-N query. Find the lowest two salaries in the company.(Notice that in our database, the two lowest salaries are 25K and 30K.)
SQL
SQL stands for Structured Query Language, is a form of communication that uses queries structured in a specific format to store, manage & retrieve data from a relational database.
Queries
A query is a type of computer programming language that is used to retrieve data from a database. Databases are useful in a variety of ways. They enable the retrieval of records or parts of records, as well as the performance of various calculations prior to displaying the results. A search query is one type of query that many people perform several times per day. A search query is executed every time you use a search engine to find something. When you press the Enter key, the keywords are sent to the search engine, where they are processed by an algorithm that retrieves related results from the search index. Your query's results are displayed on a search engine results page, or SER.
SQL Commands for:
1.) TOP-N query. Find the ssn, lname, and salary of the four highest paid employees.
2.) TOP-N query. Find the ssn, lname, and salary of the four lowest paid employees
3.) TOP-N query. Find the lowest two salaries in the company.(Notice that in our
4.) TOP-N query. For every employee whose salary is equal to one of the two lowest salaries, Find the ssn, lname, and salary.
5.)RANK query Find the rank of the salary 30000 among all salaries. (HINT: The ranks in our database are 1 for 25000, 4 for 30000, 5 for 38000, and so on.)
6.) RANK query ... compare with the previous query. Find the rank of the salary 31000 among all salaries.
7.) DENSE RANK query Find the dense rank of the salary 30000 among all salaries. Hint: The dense ranks in our database are 1 for 25000, 2 for 30000, 3 for 38000, and so on.
8.) DENSE RANK query ... compare with the previous query. Find the dense rank of the salary 31000 among all salaries. Hint: The dense ranks in our database are 1 for 25000, 2 for 30000, 3 for 38000, and so on.
9.) HIERARCHICAL query (uses START WITH and CONNECT BY PRIOR) Find pairs of SSN's such that the first SSN in the pair is that of an employee while the second SSN in the pair is that of his/her supervisor. Start with SSN 453453453.
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