Welcome to your SQL Exam

Name

Email

Course

Phone

What is the output of this query? 3 Marks

Names of employees managing projects

Names of all project managers only

Names of all employees regardless of project status

Names of employees not managing any project

Why is EXPLAIN used here? 2 Marks

To count the matching rows only

To execute the query faster

To analyze how the database will execute the query

To preview rows before selection

What does this query do? 3 Marks

Deletes old pending orders

Updates all orders to Shipped regardless of date

Ships all new orders only

Changes status of orders before 2025-01-01 to Shipped if they are Pending

Which clause is used to sort the result-set?

GROUP BY

ORDER BY

FILTER

SORT

Which of the following is a valid way to create a foreign key?

ALTER TABLE ADD RELATION

FOREIGN KEY (col) REFERENCES table(col)

KEY FOREIGN (col)

CREATE FK (col) IN table(col)

What does this query fetch? 3 Marks

Employees from all locations except New York

Departments in New York

Names of all departments

Names of employees working in New York departments

Which SQL function is used for ranking rows? 2 Marks

DENSE_RANK()

ROW_NUMBER()

All of the above

RANK()

What does this query return? 2 Marks

Employees earning less than the average salary

The average salary itself

All employee names and salaries

Employees earning more than the average salary

What will COUNT(*) return?

Number of rows including NULL values

Number of rows excluding NULL values

Average of numeric columns

Sum of numeric columns

What will this query return? 3 Marks

Customers with no payments

All payments sorted by amount

Customer(s) with the highest total payment amount

All customers with any payment amount

What will be the final result? 3 Marks

No changes will be saved

Changes saved only for the second update

Balance transferred successfully

Partial transfer completed

What does this query return? 3 Marks

All departments with employee counts

Department with the largest number of employees

Department with the smallest number of employees

All employees without grouping

What is the role of HAVING here? 2 Marks

Sorts the salary

Joins two tables

Filters groups after calculating the average salary

Filters employees before grouping

What does this query return?

All employees regardless of salary

Employees earning less than 40,000 or more than 60,000

Employees earning exactly 40,000 or 60,000

Employees earning between 40,000 and 60,000 (inclusive)

What does the EXPLAIN command do in SQL? 2 Marks

Checks syntax errors

Optimizes queries automatically

Shows table schema

Analyzes query execution plan

A subquery inside a WHERE clause is called:

Nested query

Trigger

Correlated query

Constraint

What does this query return? 2 Marks

All employees older than 30 (name and age)

All columns of employees older than 30

Only names of employees older than 30

Names and ages of all employees regardless of age

What does the DISTINCT keyword do?

Ensures only unique values are returned

Deletes duplicate rows

Sorts the result

Filters NULL values

Which type of JOIN returns all rows from both tables, even if there is no match?

RIGHT JOIN

LEFT JOIN

INNER JOIN

FULL OUTER JOIN

The default sorting order of ORDER BY is:

Random

None of the above

Ascending

Descending

What does HAVING do in SQL?

Limits result set

Filters groups after aggregation

Filters rows before grouping

Joins two tables

What extra information does WITH ROLLUP provide?

Adds a total sum across all departments

Removes duplicates from the sum

Sorts results by salary

Adds a subtotal for each employee

Which SQL statement is used to extract data from a database?

EXTRACT

PULL

SELECT

GET

What will this return? 2 Marks

All employees, even without department info

Only department names without employees

Employees without department information

Employees matched with their departments

What is the purpose of DISTINCT here? 2 Marks

Returns unique department names only

Counts department occurrences

Returns all department names including duplicates

Sorts the departments alphabetically

Which of these is not a SQL data type?

ARRAYLIST

VARCHAR

INTEGER

FLOAT

What is the purpose of COMMIT in SQL?

Save changes permanently

Close a transaction

Undo changes

Lock a table

What does this query produce? 2 Marks

Employees sorted alphabetically

Employees ranked by salary, highest first

Average salary per department

Employees grouped by salary

Which statement about window functions is incorrect? 2 Marks

They can be used with OVER() clause

Examples include RANK() and LEAD()

They operate on a set of rows related to the current row

They modify the number of rows returned

SQL ( Interview Questions ) Exam