Consider the following relation : Works (emp_name, company_name, salary) Here, emp_name is primary key. Consider the following SQL query Select emp_name From works T where salary > (select avg (salary) from works S where T.company _ name = S.company _ name) The above query is for following :
Find all employees who earn more than the average salary of all employees of their company.
The query uses a correlated subquery: the inner query refers to T, the tuple variable of the outer query, so it is re-evaluated for every row of the outer relation.
Step 1 — For a given outer row T, the inner query computes avg(salary) over all rows S of works with S.company_name = T.company_name, i.e. the average salary of the employees of T's own company.
Step 2 — The outer WHERE keeps row T if T.salary is greater than that company-wise average, and SELECT returns T.emp_name. No MAX or ordering is applied, so every qualifying employee is returned, not just one.
Step 3 — The result is therefore the set of all employees whose salary exceeds the average salary of their own company.
Descriptions that speak of 'the highest paid employee' are wrong because nothing restricts the result to a single top earner. Descriptions comparing with the average over all companies would need an uncorrelated subquery (select avg(salary) from works) without the company-name condition.
Find all employees who earn more than the average salary of all employees of their company. option is correct.
Similar Questions
Consider the following three SQL queries (Assume the data in the people table) :
(a) Select Name from people where Age>21;
(b) Select Name from people where Height>180;
(c) Select Name from people where (Age>21) or (Height>180);
If the SQL queries (a) and (b) above, return 10 rows and 7 rows in the result set respectively, then what is one possible number of rows returned by the SQL query (c) ?
Suppose ORACLE relation R(A, B) currently has tuples {(1, 2), (1, 3), (3, 4)} and relation S(B, C) currently has {(2, 5), (4, 6), (7, 8)}. Consider the following two SQL queries SQ1 and SQ2 :
SQ1 : Select *
From R Full Join S
On R.B = S.B;
SQ2 : Select *
From R Inner Join S
On R.B = S.B;
The numbers of tuples in the result of the SQL query SQ1 and the SQL query SQ2 are given by :
Consider a “CUSTOMERS” database table having a column “CITY” filled with all the names of Indian cities (in capital letters). The SQL statement that finds all cities that have “GAR” somewhere in its name, is :
The STUDENT information in a university stored in the relation STUDENT (Name, SEX, Marks, DEPT_Name)
Consider the following SQL Query SELECT DEPT_Name from STUDENT where SEX = ‘M’ group by DEPT_Name having avg (Marks)>SELECT avg (Marks) from STUDENT. It Returns the Name of the Department for which :
An Assertion is a predicate expressing a condition we wish database to always satisfy. The correct syntax for Assertion is :
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 Codes :
Given query:
select s.rollno, s.name
from student s
where EXISTS (select c.courseid from course c Where c.deptno=5 and
EXISTS (select e.* from enrollemnt e
where e.courseid = c.courseid and
e.rollno = s.rollno));
Which one of the following statements is correct with respect to the given query?
Which of the following queries would retrieve the dept id and name of all the departments that are such that the total of the credits of all the offered courses by the department is strictly greater than 40?
Which of the following queries would compute, for each department, the total credits of all the courses offered by the department?
Given query: select s.rollno from students where s.sex = ALL (select f.sex from professor f where f.empid = s.advisor)
Consider the following statements about the given query that retrieves the set of all students whose gender is same as the gender of their advisor:
S1. It has a correlated subquery
S2. It has an uncorrelated subquery
S3. If we replace ALL by ANY in the above query, its result will be different
S4. If we replace ALL by ANY in the above query, its result will be same.
Identify all the statement that are TRUE:
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 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)
Consider the following two tables named Raider and Team in a relational database maintained by a Kabaddi league. The attribute ID in table Team references the primary key of the Raider table, ID.
Raider ID Name Raids RaidPoints 1 Arjun 200 250 2 Ankush 190 219 3 Sunil 150 200 4 Reza 150 190 5 Pratham 175 220 6 Gopal 193 215 Team City ID BidPoints Jaipur 2 200 Patna 3 195 Hyderabad 5 175 Jaipur 1 250 Patna 4 200 Jaipur 6 200 The SQL query described below is executed on this database:
SELECT *
FROM Raider, Team
WHERE Raider.ID=Team.ID AND City="Jaipur" AND
RaidPoints > 200;
The number of rows returned by this query is ________.
