GATE DA 2026 Set 1 — Question 51

MSQ+2 / -0MediumAggregate FunctionsSQLDatabase Management & WarehousingFiltering, Grouping & Nested QueriesJoins

Database Management & Warehousing → SQL → Aggregate Functions

Last updated 5 September 2026

Question

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 182838475769 Output EmpID TeamSize 132333425261

Your answer

Select all that apply, then check your answer.

SELECT E.EmpID, B.TeamSize FROM Employee AS E, (SELECT TeamID, COUNT(TeamID) AS TeamSize FROM Employee GROUP BY TeamID) AS B WHERE E.TeamID = B.TeamID

SELECT A.EmpID, COUNT(B.TeamID) AS TeamSize FROM Employee AS A, Employee AS B WHERE A.TeamID = B.TeamID AND A.EmpID = B.EmpID GROUP BY A.EmpID

SELECT B.EmpID, B.TeamSize FROM (SELECT EmpID, COUNT(TeamID) AS TeamSize FROM Employee GROUP BY EmpID) AS B

SELECT A.EmpID, B.TeamSize FROM Employee AS A, (SELECT COUNT(TeamID) AS TeamSize FROM Employee GROUP BY TeamID) AS B WHERE A.TeamID = B.TeamID

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Correct answer (A) [code] Solution We need to calculate the size of each team and then join it back to the employees to show the size for each employee. Option A: Correct. The subquery B calculates the count (TeamSize) for each TeamID . The outer query joins the Employee table E with B on TeamID, correctly associating each employee with their team's size. Option B: Incorrect. The condition A.EmpID = B.EmpID restricts the join to only match the employee with themselves. The count will always be 1 for every employee. To be correct, it should be WHERE A.TeamID = B.TeamID without the EmpID equality check, or a proper self-join logic. Option C: Incorrect. GROUP BY EmpID will result in a count of 1 for each row (since EmpID is the primary key), not the team size. Option D: Incorrect. The subquery SELECT COUNT(TeamID) AS TeamSize FROM Employee GROUP BY TeamID returns a list of counts but does not select the TeamID column. Therefore, the join condition WHERE A.TeamID = B.TeamID is invalid because B does not have a TeamID column. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) [code] Solution We need to calculate the size of each team and then join it back to the employees to show the size for each employee. Option A: Correct. The subquery B calculates the count (TeamSize) for each TeamID . The outer query joins the Employee table E with B on TeamID, correctly associating each employee with their team's size. Option B: Incorrect. The condition A.EmpID = B.EmpID restricts the join to only match the employee with themselves. The count will always be 1 for every employee. To be correct, it should be WHERE A.TeamID = B.TeamID without the EmpID equality check, or a proper self-join logic. Option C: Incorrect. GROUP BY EmpID will result in a count of 1 for each row (since EmpID is the primary key), not the team size. Option D: Incorrect. The subquery SELECT COUNT(TeamID) AS TeamSize FROM Employee GROUP BY TeamID returns a list of counts but does not select the TeamID column. Therefore, the join condition WHERE A.TeamID = B.TeamID is invalid because B does not have a TeamID column.

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