Welcome to your SQL Exam

Name

Email

Course

Phone

What does this query return? 2 Marks

All columns of employees older than 30

Only names of employees older than 30

All employees older than 30 (name and age)

Names and ages of all employees regardless of age

Which SQL function is used for ranking rows? 2 Marks

All of the above

RANK()

DENSE_RANK()

ROW_NUMBER()

The default sorting order of ORDER BY is:

Random

None of the above

Descending

Ascending

What extra information does WITH ROLLUP provide?

Adds a total sum across all departments

Sorts results by salary

Removes duplicates from the sum

Adds a subtotal for each employee

What does this query fetch? 3 Marks

Names of all departments

Employees from all locations except New York

Names of employees working in New York departments

Departments in New York

Which of these is not a SQL data type?

VARCHAR

INTEGER

FLOAT

ARRAYLIST

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 SQL statement is used to extract data from a database?

EXTRACT

SELECT

PULL

GET

What will COUNT(*) return?

Average of numeric columns

Sum of numeric columns

Number of rows including NULL values

Number of rows excluding NULL values

Which statement about window functions is incorrect? 2 Marks

They modify the number of rows returned

Examples include RANK() and LEAD()

They can be used with OVER() clause

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

Which clause is used to sort the result-set?

FILTER

SORT

ORDER BY

GROUP BY

A subquery inside a WHERE clause is called:

Correlated query

Constraint

Nested query

Trigger

What will this return? 2 Marks

All employees, even without department info

Employees without department information

Employees matched with their departments

Only department names without employees

What is the role of HAVING here? 2 Marks

Filters groups after calculating the average salary

Joins two tables

Sorts the salary

Filters employees before grouping

What does the EXPLAIN command do in SQL? 2 Marks

Checks syntax errors

Shows table schema

Analyzes query execution plan

Optimizes queries automatically

What will this query return? 3 Marks

All payments sorted by amount

All customers with any payment amount

Customer(s) with the highest total payment amount

Customers with no payments

What is the output of this query? 3 Marks

Names of employees not managing any project

Names of all project managers only

Names of all employees regardless of project status

Names of employees managing projects

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

KEY FOREIGN (col)

ALTER TABLE ADD RELATION

CREATE FK (col) IN table(col)

FOREIGN KEY (col) REFERENCES table(col)

What will be the final result? 3 Marks

Partial transfer completed

Changes saved only for the second update

Balance transferred successfully

No changes will be saved

Why is EXPLAIN used here? 2 Marks

To execute the query faster

To preview rows before selection

To analyze how the database will execute the query

To count the matching rows only

What does this query return? 3 Marks

Department with the smallest number of employees

All departments with employee counts

Department with the largest number of employees

All employees without grouping

What does this query do? 3 Marks

Ships all new orders only

Updates all orders to Shipped regardless of date

Deletes old pending orders

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

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

FULL OUTER JOIN

RIGHT JOIN

INNER JOIN

LEFT JOIN

What does the DISTINCT keyword do?

Sorts the result

Filters NULL values

Ensures only unique values are returned

Deletes duplicate rows

What does this query return? 2 Marks

All employee names and salaries

Employees earning more than the average salary

Employees earning less than the average salary

The average salary itself

What is the purpose of COMMIT in SQL?

Undo changes

Close a transaction

Save changes permanently

Lock a table

What does HAVING do in SQL?

Limits result set

Joins two tables

Filters rows before grouping

Filters groups after aggregation

What does this query produce? 2 Marks

Employees sorted alphabetically

Employees ranked by salary, highest first

Employees grouped by salary

Average salary per department

What does this query return?

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

All employees regardless of salary

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

Employees earning exactly 40,000 or 60,000

SQL ( Interview Questions ) Exam