Consider the following tables (relations): Students: Roll-No Name 18CS101 Ramesh 18CS102 Mukesh 18CS103 Ramesh Performance: Roll-No Course Marks 18CS101 DBMS 60 18CS101 Compiler Design 65 18CS102 DBMS 80 18CS103 DBMS 85 18CS102 Compiler Design 75 18CS103 Operating System 70 Primary keys in the tables are shown using Underline. Now, Consider the following query: SELECT S.Name, Sum (P.Marks) FROM Students S, Performance P WHERE S.Roll-No = P.Roll-No GROUP BY S.Name The number of rows returned by the above query is
2
GROUP BY S.Name creates one group for each distinct name in the joined rows. The two groups are Ramesh, with total marks 60 + 65 + 85 + 70 = 280, and Mukesh, with total marks 80 + 75 = 155. Hence the query returns 2 rows.
Important Questions from SQL
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 Which of the following is NOT a Structured Query Language Data type?
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?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 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)
