Welcome to your SQL Exam

Name

Email

Course

Phone

What will this query return? 3 Marks

Customer(s) with the highest total payment amount

Customers with no payments

All customers with any payment amount

All payments sorted by amount

What is the role of HAVING here? 2 Marks

Sorts the salary

Filters employees before grouping

Filters groups after calculating the average salary

Joins two tables

What does the EXPLAIN command do in SQL? 2 Marks

Checks syntax errors

Shows table schema

Analyzes query execution plan

Optimizes queries automatically

The default sorting order of ORDER BY is:

Random

Descending

None of the above

Ascending

What will this return? 2 Marks

Employees without department information

Only department names without employees

All employees, even without department info

Employees matched with their departments

What does the DISTINCT keyword do?

Ensures only unique values are returned

Deletes duplicate rows

Sorts the result

Filters NULL values

What will be the final result? 3 Marks

Balance transferred successfully

No changes will be saved

Changes saved only for the second update

Partial transfer completed

Which statement about window functions is incorrect? 2 Marks

They modify the number of rows returned

Examples include RANK() and LEAD()

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

They can be used with OVER() clause

What is the purpose of DISTINCT here? 2 Marks

Returns unique department names only

Returns all department names including duplicates

Sorts the departments alphabetically

Counts department occurrences

Which clause is used to sort the result-set?

GROUP BY

FILTER

ORDER BY

SORT

Which SQL function is used for ranking rows? 2 Marks

All of the above

DENSE_RANK()

RANK()

ROW_NUMBER()

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

What extra information does WITH ROLLUP provide?

Adds a subtotal for each employee

Adds a total sum across all departments

Removes duplicates from the sum

Sorts results by salary

What does this query return? 2 Marks

Employees earning more than the average salary

Employees earning less than the average salary

All employee names and salaries

The average salary itself

Which of these is not a SQL data type?

ARRAYLIST

INTEGER

VARCHAR

FLOAT

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

FOREIGN KEY (col) REFERENCES table(col)

ALTER TABLE ADD RELATION

CREATE FK (col) IN table(col)

KEY FOREIGN (col)

What does this query return? 3 Marks

All employees without grouping

Department with the smallest number of employees

All departments with employee counts

Department with the largest number of employees

What does this query produce? 2 Marks

Average salary per department

Employees ranked by salary, highest first

Employees grouped by salary

Employees sorted alphabetically

What does this query fetch? 3 Marks

Names of all departments

Employees from all locations except New York

Departments in New York

Names of employees working in New York departments

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

SELECT

EXTRACT

PULL

GET

What is the purpose of COMMIT in SQL?

Save changes permanently

Close a transaction

Undo changes

Lock a table

What does this query return? 2 Marks

Names and ages of all employees regardless of age

All columns of employees older than 30

Only names of employees older than 30

All employees older than 30 (name and age)

A subquery inside a WHERE clause is called:

Constraint

Nested query

Trigger

Correlated query

What will COUNT(*) return?

Sum of numeric columns

Number of rows excluding NULL values

Average of numeric columns

Number of rows including NULL values

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

LEFT JOIN

INNER JOIN

RIGHT JOIN

FULL OUTER JOIN

What does this query return?

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

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

Employees earning exactly 40,000 or 60,000

All employees regardless of salary

What does HAVING do in SQL?

Filters groups after aggregation

Joins two tables

Filters rows before grouping

Limits result set

What does this query do? 3 Marks

Deletes old pending orders

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

Updates all orders to Shipped regardless of date

Ships all new orders only

Why is EXPLAIN used here? 2 Marks

To preview rows before selection

To count the matching rows only

To execute the query faster

To analyze how the database will execute the query

SQL ( Interview Questions ) Exam