Consider the following SQL query on the university schema: SELECT AVG(salary) - (SUM(salary)/COUNT(*)) FROM instructor; We might expect that the result of this query is zero since the average of a set of numbers is defined to be the sum of the numbers divided by the number of numbers. Indeed, this is true for the example instructor relation in Figure 2.1. However, there are other possible instances of that relation for which the result would NOT be zero. Give one such instance, and explain why the results would not be zero

Q: After executing a Cartesian product of student and advisor, followed by a selection operation on the…

A: ALGEBRA OF RELATIONS: Relational algebra is essentially a query language that accepts as input…

Q: SQL allows a foreign-key dependency to refer to the same relation, as in the following example:…

A: Answer:-

Q: Consider the following sales relational database schema for sales. tem (ItemNo: integer, itemName…

A: Below is the answer of the above query. I hope this will be helpful for you...

Q: Given the relation schema R(A, B, C) and S(C, D, E), please match each of the following relational…

A: ANSWER:

Q: Consider the following relational schema Sailors(sid, sname, rating, age) Reserves(sid, bid, day)…

A: 1.SELECT B.bid,B.bname,B.size FROMBoats AS BJOINReserves AS RON B.bid=R.bidJOINSailors AS SON…

Q: Consider the bank database of Figure 15.14, where the primary keys are underlined, and the following…

A: Explanation:   The below expression performs the theta join on the smallest amount of data…

Q: Explain why an index is only helpful if an attribute's values are sufficiently diverse.

A: Introduction Use of an index with a wide range of values A file index is a table or other data…

Q: 1- Draw an ERD about a restaurant on Oracle SQL developer data modeler, it should contain at least 8…

A: Answer: I have given answered in the handwritten format in brief explanation.

Q: Write Queries in Relational Algebra = sleer (r) = From T =where Op(7) Consider the following schema:…

A: Solution:   Given,

Q: Consider the following SQL query on the university schema:          select avg(salary)-(sum(salary)…

A: For numeric values it will always be zero. But when there is a null value the answer will be…

Q: Let R and S be two relations with the following schema: R (P.Q. R1, R2, R3) S (P.Q S1, S2) Where (P,…

A: Let R and S be two relations with the following schema R(P,Q−−−−,R1,R2,R3)R(P,Q_,R1,R2,R3)…

Q: Consider the relation R (A, B, C) with an index on attribute A. a. Give an example of a query that…

A: The answer is as follows.

Q: What is the result of first performing the cross product of student and advisor, and then performing…

A: Introduction: Cross Product: Cartesian Product in DBMS is an operation used to merge columns from…

Q: MPLOYEE FNAME MINIT LNAME SSN BDATE ADDRESS SEX SALARY DNO DEPARTMENT DNAME DNUMBER MGRSSN…

A:

Q: Print all the computer sciences courses, these courses with code start with ‘CS’ sorted…

A: As per our company guidelines, we are supposed to answer only three subparts of question and kindly…

Q: Consider the relations r(A, B, D), and s(B, D, F), in which A, B, D and F are their attributes. The…

A: Here in the query, I have taken the 'some' part as s.B, But you can modify it according to your…

Q: PART B Consider the college database you implemented in the image provided and answer the following…

A: Solution: 1.SQL statement that displays the data of the STUDENTS table SQL Query to create table1 :…

Q: Testing SQL queries: To test if a query specified in English has been correctlywritten in SQL, the…

A: Reason for using query In the query, select * from teaches natural join instructor; In the above…

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Q: Given the database schema R(A, B, C), and a relation r on the schema R, write an SQL query to test…

A: Functional dependency An attribute C does have a functional dependency on valid instances of…

Q: PLZ help with the following: IN SQL Let R (A, B, C) be a relation schema. What happens if we…

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Q: SQL allows relations with duplicates (Chapter 3), and the multiset version of the relational algebra…

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Q: Consider the following Relation instance of Students: ID firstNamelastName GPA Address 123 Albertson…

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Q: Given the relation schema R(A, B, C) and S(C, D, E), please match each of the following relational…

A: ANSWER:

Q: What will be the result of the following SQL query for the instance of the relation INVENTORY…

A: Introduction :Given , a sql query .we have asked for the result of this query.

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A: Answer: Given Query: SELECT city, amount FROM Customers INNER JOIN Orders ON…

Q: Consider the following sales relational database schema for sales.   Item (ItemNo: integer,…

A: SELECT          i.itemName,         i.type      FROM item i     INNER JOIN Sales s          ON…

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Q: In SQL, foreign key constraints can reference only the primary key attributes ofthe referenced…

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A: In a relational database, a primary key, also identified as main keywords, is a key that is unique…

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A: The cartesian product allows us to combine information from any two relations. The cartesian product…

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Q: Q1. (Extended Relational Algebra): Here are two relations: R(A,B): {(0,1),(2,3),(5,2)}, S(B,C):…

A: Solution for above question is given below -

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A:

Q: Although SQL does not support functional dependency constraints, if thedatabase system supports…

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A:

Q: Consider the following SQL query on the university schema:select avg(salary) - (sum(salary) /…

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A:

Q: Consider the library database of Figure 3.20. Write the following queries in SQL.Find the average…

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Q: What is the result of first performing the cross product of student and advisor, and then performing…

A: Answer:

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Intermediate SQL Concepts

A query is a request for data or information from one or more database tables. This information could be presented in the form of pictorials, graphs, or complicated findings which helps in easy interpretation. Structured Query Language (SQL) is the most widely used programming language for retrieving and organizing data from relational databases. Collection of tables with rows and columns is referred to as a database. SQL is the language of databases. It makes it easier to extract specific data from databases, which can then be used for analysis.