C++ and SQL Online Test
TestDome skill assessments are used by more than 5,000 companies and 450,000 individual test takers.
Jobseekers: Get a Certificate
Take a Practice TestCompanies: Try First, Pay Later
Sign Up To Use This TestThe C++ and SQL online test assesses candidates' knowledge of programming in the C++ language and their ability to use SQL.
It's an ideal test for pre-employment screening. A good C++ developer needs to be able not only to solve problems using C++ but also to write and analyze SQL queries to access a database.
This online test requires candidates to solve coding problems in C++ and to write SQL queries that extract, combine, and manipulate data.
Recommended Job Roles
Back-End Developer
C++ Developer
SQL Developer
Sample Candidate Report
Sample Free Questions
Students
3min
-
Easy
Easy
-
CODE
SQL
Aggregation
Select
Public
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Aggregation
An aggregate function is typically used in database queries to group together multiple rows to form a single value of meaningful data. A good programmer should be skilled at using data aggregation functions when interacting with databases.
Select
The SELECT statement is used to select data from a database. It is the most used SQL command.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Given the following data definition, write a query that returns the number of students whose first name is John. String comparisons should be case sensitive.
TABLE students id INTEGER PRIMARY KEY, firstName VARCHAR(30) NOT NULL, lastName VARCHAR(30) NOT NULL
Enrollment
5min
-
Easy
Easy
-
CODE
SQL
Conditions
Update
Public
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Conditions
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Update
The UPDATE statement is used to modify the existing records in a table and is one of the most used operations for working with the database.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
A table containing the students enrolled in a yearly course has incorrect data in records with ids between 20 and 100 (inclusive).
TABLE enrollments id INTEGER NOT NULL PRIMARY KEY year INTEGER NOT NULL studentId INTEGER NOT NULL
Write a query that updates the field 'year' of every faulty record to 2015.
Merge Names
10min
-
Easy
Easy
-
CODE
C++
Arrays
Public
C++
The C++ language provides imperative, object-oriented and generic programming features, while also providing facilities for low-level memory manipulation. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Public
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Implement the unique_names method. When passed two vectors of names, it will return a vector containing the names that appear in either or both vectors. The returned vector should have no duplicates.
For example, calling unique_names(std::vector<std::string>{"Ava", "Emma", "Olivia"}, std::vector<std::string>{"Olivia", "Sophia", "Emma"}) should return a vector containing Ava, Emma, Olivia, and Sophia in any order.
Premium Questions
The premium question library contains our unique, hand-crafted questions. We offer a refund if you find any of them answered online.
Questions
Non Zero, Document Store, Babushka Doll, Roads, Out of Range, Tiles, Needle, Max Sum, Paper Strip, Shipping, Ingredients, Read Write Execute, Limits, Stories, Runner, Segment, Archive, ATM Locations, Authors, Autocomplete, Ban Users, Bank Branches, Chain Link, Cheapest Product, Chicken, Countries, Crop Ratio, Date Transform, Department Report, Developers, Employee Manager, Veterinarian, Hobbies, Hospital Patients, Index Performance, Menu Items, Merge Stock Index, Movies, Movies Live, Projects, Rectangles, Restaurant Menu, Retirees, Sales, SMS Messages, Student Activities, Tasks, Transactions, Youngest Child, Increment, Increment, Internal Nodes, Node, Paragraph, Platformer, Stack to Vector, Ship, Unique Product, Unique Numbers, Username, Weighted Average, Window Manager, Welfare Organization, Manager Sales, Battery, Delete Orders, Book Sale, Friend, Function Cache, Student Max Score, Average Salary, Movie Genres, Student Rankings, Auto Show, Poll, Moving TotalSkills
C++C++
The C++ language provides imperative, object-oriented and generic programming features, while also providing facilities for low-level memory manipulation. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
Bug fixing
Everyone makes mistakes. A good programmer should be able to find and fix a bug in their or someone else's code.
Language
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
Memory management
Memory management allows programs to request memory dynamically from the operating system, and free it for reuse when no longer needed. Many modern programming languages automate this process; however, it should still be an important consideration when implementing an application.
SQL
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Conditions
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Views
A database view is a result set that is defined by a stored query, the results of which can can also be queried. As a fundamental and widely used database construct, it's useful for candidates to understand how and when they should be used.
Exceptions
Exceptions exist in most modern programming languages, making it important for a programmer to understand them and know how to handle them.
Vector
Vectors are one-dimensional collections that act as dynamic arrays. In many languages, Vectors offer the flexibility of dynamically sized arrays, the simplicity of access of arrays, and are more performant than more ubiquitous collections in most scenarios.
Stream
A stream is a sequence of data elements made available over time. It is particularly useful for tasks that may benefit from being asynchronous, including tasks such as I/O processing or reading from a file, and as such is important for developers to understand.
Strings
The string data structure is used to represent text. It is one of the most commonly used data structures. Therefore, every programmer should be skilled at string manipulation.
Algorithmic thinking
When designing and/or analyzing an algorithm or data structure, it is important to consider the performance and structure of an implementation. Algorithmic thinking is one of the key traits of a good programmer, especially one working on complex or performance-critical code.
Arithmetic
Arithmetic is a fundamental branch of mathematics. An understanding of arithmetic concepts, and their application, is important for every candidate.
Subqueries
Subqueries are commonly used in database interactions, making it important for a programmer to be skilled at writing them.
Update
The UPDATE statement is used to modify the existing records in a table and is one of the most used operations for working with the database.
Conditional statements
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Dynamic programming
Dynamic programming methods for code optimization can be very useful to a programmer who understands them.
Destructors
A destructor is a special member function that is called when the lifetime of an object ends. Developers should use them to free (unmanaged) resources that the object may have acquired during its lifetime.
Constraints
Constraints are used to define rules and relationships. They are applied to a dataset. A constraint may take many forms, such as x ≤ 5 in a programming language and a NOT NULL constraint in a SQL table definition.
Create table
The CREATE TABLE statement is used to create a new table in a database. It is an essential command when creating new database.
Database schema
A database schema defines how data is stored in a database. An SQL database uses a schema to define tables consisting of rows and columns that use fixed data types to store data. Formalizing how data is stored is the first step towards building an application or service.
Select
The SELECT statement is used to select data from a database. It is the most used SQL command.
Create index
The CREATE INDEX statement is used to create indexes for tables. Indexes are used to retrieve data from the database more quickly. They are very important for making performant queries.
Performance tuning
The performance of an application or system is important. The responsiveness and scalability of an application are all related to how performant an application is. Each algorithm and query can have a large positive or negative effect on the whole system.
Alter table
The ALTER TABLE statement is used to add, delete, or modify columns and constraints in an existing table. Alter table statements are important for all programmers who have to modify existing schemas.
Linked list
A linked list is a linear collection of data elements where each element points to the next. It is a data structure consisting of a collection of nodes which together represent a sequence. It is usually used for advanced scenarios where we need fast access to the next element, or when we need to remove an element from anywhere in the collection.
Aggregation
An aggregate function is typically used in database queries to group together multiple rows to form a single value of meaningful data. A good programmer should be skilled at using data aggregation functions when interacting with databases.
Higher order function
A higher order function is a function that takes another function as an argument, or returns another function. Developers often use them for writing reusable code.
Interfaces
An interface is used to define an abstract type that defines behaviors as method signatures. Instances of different types can implement the same interface and provide a way for a developer to reuse the code.
OOP
Object-oriented programming is a paradigm based on encapsulating logic and data into objects, which may then contain fields and procedures. Many of the most widely used programming languages are based on OOP, making it a very important concept in modern programming.
Ordering
Knowing how to order data is a common task for every programmer.
Integer division
Integer division is division in which the fractional part (remainder) is discarded. Knowing this is important for optimal implementation of some algorithms and for avoiding common bugs.
Regex
A regular expression (regex) is a special text string for describing a search pattern. It is a common way for extracting data from text.
Insert
Even though most database insert queries are simple, a good programmer should know how to handle more complicated situations like batch inserts.
Left join
LEFT JOIN is one of the ways to merge rows from two tables. We use it when we also want to show rows that exist in one table, but don't exist in the other table.
Queue
A queue is a collection of items that are maintained in a sequence and can be modified by the addition of entities at one end of the sequence and removal from the other end of the sequence. It is the collection to be used when first-in-first-out (FIFO) collection is needed.
Iteration
Iteration is the act of repeating a process, or cycling through a collection. Iteration is one of the fundamental flow control tools available to developers.
Map
Map is a data type composed of a collection of key-value pairs, where each possible key appears at most once in the collection. It is used when we need to access items by their keys and we need to know their order.
Indexes
The proper implementation and use of indexes are important for improving the performance of database queries.
Union
The UNION operator is used to combine the result-set of two or more SELECT statements. It is often used when a report needs to be made based on multiple tables.
Group by
The GROUP BY statement groups rows by some attribute into summary rows. It is a common command when making various reports.
Joins
A normalized database is normally made up of multiple tables. Joins are, therefore, required to query across multiple tables.
Pointers
A pointer references a location in memory, and obtaining the value stored at that location is known as dereferencing the pointer. Using pointers is something that all C and C++ developers should know.
Arrays
An array is a container of a fixed number of objects of a similar type. It is a fundamental component of most programming languages.
Tree
A tree is a hierarchical structure defined recursively starting with the root node, where each node is a data structure consisting of a value, together with a list of references to other nodes (the "children"). A lot of problems can be solved efficiently with trees, which makes them important for developers.
Recursion
A good programmer should be familiar with when to use recursive functions, since they can provide elegant solutions for complex problems.
Data structures
Choosing the right data structure to solve a problem can have huge implications on the performance of an application. Knowing when to use a specific data structure is one of the most important skills for a programmer.
Complexity
A good programmer should be able to analyze and plan for the performance of an algorithm.
Stack
A stack is dynamic data container that follows the Last In First Out (LIFO) principle. Developers should use stack when the last item to be inserted into a container is the first one to be deleted from it.
Unordered map
Unordered map (or dictionary) is a data type composed of a collection of key-value pairs, where each possible key appears at most once in the collection. It is used when we need to access items by their keys.
SQL CASE
The CASE statement is SQL's control statement. It goes through conditions and returns a value.
CTE
A CTE (Common Table Expression) is a temporary result set that can be referenced within another SELECT, INSERT, UPDATE, or DELETE statement. Recursive CTEs can reference themselves, which enables developers to work with hierarchical data.
Delete
The delete statement is used to delete records in a table and is one of the four basic CRUD functions (create, read, update, and delete) required for working with any persistent storage.
Sorting
Every programmer should be familiar with data-sorting methods, as sorting is very common in data-analysis processes.
Graphs
Many real-life situations are best modeled by graphs. Therefore, an in-depth knowledge of graph data structures is important for a good programmer.
Hash and equals
A hash function is any function that can be used to map data of arbitrary size to fixed-size values. Developers should know how to properly implement hash and equals functions to optimally use key-value collections like dictionaries.
Unordered set
Unordered set is a container that stores unique elements in no particular order, and which allow for fast retrieval of individual elements based on their value.
Score Distribution
# of candidates
| 0-33% | |
|---|---|
| 34-66% | |
| 67-100% |
Score