Important Questions from SQL

1. Match the following -

   List I		List II
   (a)	DDL	(i)	LOCK TABLE
   (b)	DML	(ii)	COMMIT
   (c)	TCL	(iii)	Natural Difference
   (d)	Binary operation	(iv)	REVOKE

   DBMS

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2. Which of the following is NOT a Structured Query Language Data type?

   DBMS

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3. Consider the following relational schema:
   Students (rollno: integer, name: string, age: integer, cgpa: real)
   Courses (courseno: integer, cname: string, credits: integer)
   Enrolled (rollno: integer, courseno: integer, grade: string)
   Which of the following options is/are correct SQL query/queries to retrieve the names of the students enrolled in course number (i.e., courseno) 1470?

   DBMS

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4. Consider a table Employee(EmpID, TeamID), where the column EmpID (ID of an employee) is the primary key. The column TeamID denotes the team ID of the team of which the employee is a member. TeamID is a NOT NULL column.
   
   We want to display the size of the team (denoted as TeamSize) in which each employee is a member by using SQL. As an example, the desired output for the given Employee table is also shown in tabular form.

   Which of the following is/are correct?
   
   Employee
    

   EmpID	TeamID
   1	8
   2	8
   3	8
   4	7
   5	7
   6	9

   
   
   Output
    

   EmpID	TeamSize
   1	3
   2	3
   3	3
   4	2
   5	2
   6	1

   Database Management and Warehousing

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5. Let Account be a relation as shown. 

                                                                                                            Account

   AccNo	Balance
   A1	5000
   A2	5000
   A3	10000
   A4	15000
   A5	18000

   Consider the given SQL query.

   SELECT AccNo FROM Account AS A 

   WHERE (SELECT COUNT(*) FROM Account AS B  

   WHERE A.Balance < B.Balance) >= (SELECT COUNT(*)  

   FROM Account AS C WHERE A.Balance > C.Balance)

   The number of rows returned by the SQL query is __________ . (Answer in integer)

   Database Management and Warehousing

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