Welcome to your SQL Exam

Name

Email

Course

Phone

Which of these is not a SQL data type?

INTEGER

ARRAYLIST

VARCHAR

FLOAT

What does this query return? 2 Marks

All columns of employees older than 30

Only names of employees older than 30

Names and ages of all employees regardless of age

All employees older than 30 (name and age)

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 will this query return? 3 Marks

Customer(s) with the highest total payment amount

Customers with no payments

All payments sorted by amount

All customers with any payment amount

What does the EXPLAIN command do in SQL? 2 Marks

Checks syntax errors

Shows table schema

Optimizes queries automatically

Analyzes query execution plan

What is the purpose of COMMIT in SQL?

Save changes permanently

Lock a table

Undo changes

Close a transaction

The default sorting order of ORDER BY is:

Ascending

Random

Descending

None of the above

What does this query do? 3 Marks

Ships all new orders only

Updates all orders to Shipped regardless of date

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

Deletes old pending orders

What will be the final result? 3 Marks

No changes will be saved

Balance transferred successfully

Partial transfer completed

Changes saved only for the second update

What will this return? 2 Marks

All employees, even without department info

Only department names without employees

Employees matched with their departments

Employees without department information

What is the output of this query? 3 Marks

Names of employees managing projects

Names of employees not managing any project

Names of all employees regardless of project status

Names of all project managers only

What does this query return? 3 Marks

All departments with employee counts

Department with the smallest number of employees

All employees without grouping

Department with the largest number of employees

What does this query fetch? 3 Marks

Departments in New York

Names of employees working in New York departments

Names of all departments

Employees from all locations except New York

Which SQL function is used for ranking rows? 2 Marks

RANK()

All of the above

ROW_NUMBER()

DENSE_RANK()

What is the purpose of DISTINCT here? 2 Marks

Returns all department names including duplicates

Sorts the departments alphabetically

Returns unique department names only

Counts department occurrences

What extra information does WITH ROLLUP provide?

Removes duplicates from the sum

Adds a total sum across all departments

Adds a subtotal for each employee

Sorts results by salary

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

What does the DISTINCT keyword do?

Ensures only unique values are returned

Filters NULL values

Deletes duplicate rows

Sorts the result

What does this query return? 2 Marks

Employees earning more than the average salary

All employee names and salaries

The average salary itself

Employees earning less than the average salary

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

CREATE FK (col) IN table(col)

ALTER TABLE ADD RELATION

KEY FOREIGN (col)

FOREIGN KEY (col) REFERENCES table(col)

What does this query return?

All employees regardless of salary

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

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

Employees earning exactly 40,000 or 60,000

Which statement about window functions is incorrect? 2 Marks

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

They can be used with OVER() clause

They modify the number of rows returned

Examples include RANK() and LEAD()

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

GET

EXTRACT

PULL

SELECT

What will COUNT(*) return?

Number of rows including NULL values

Sum of numeric columns

Number of rows excluding NULL values

Average of numeric columns

A subquery inside a WHERE clause is called:

Nested query

Trigger

Correlated query

Constraint

What does HAVING do in SQL?

Filters rows before grouping

Filters groups after aggregation

Joins two tables

Limits result set

Which clause is used to sort the result-set?

GROUP BY

SORT

FILTER

ORDER BY

What is the role of HAVING here? 2 Marks

Filters groups after calculating the average salary

Filters employees before grouping

Sorts the salary

Joins two tables

What does this query produce? 2 Marks

Employees sorted alphabetically

Average salary per department

Employees ranked by salary, highest first

Employees grouped by salary

SQL ( Interview Questions ) Exam