MySQL and SQL Online Test
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Sign Up To Use This TestThe MySQL and SQL online test assesses candidates' knowledge of SQL queries, relational database concepts, and specific MySQL features.
It's an ideal test for pre-employment screening. A good database admin or back-end developer working exclusively on a MySQL server database needs to be able to use features specific to MySQL to interface efficiently with the database.
This online test requires candidates to answer multiple-choice questions about MySQL and to write SQL queries that extract, combine, or manipulate data.
Recommended Job Roles
Data Analyst
Database Administrator
MySQL Database Administrator
MySQL Developer
SQL Developer
Sample Candidate Report
Sample Free Questions
Paginate Users
3min
-
Easy
Easy
-
MCA
MySQL
Pagination
Public
MySQL
MySQL is an open-source relational database management system. It is one of the most widely used databases and is prominent in the popular LAMP stack.
Pagination
Pagination is the process of dividing data into discrete pages. It can be used to reduce the overhead of fetching large quantities of data, and as such, it is important when developing systems that fetch remote data.
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.
Consider the following table:
CREATE TABLE users (
id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(50) NOT NULL
);
The following query is used to paginate the table:
SELECT * FROM users ORDER BY username LIMIT 5 OFFSET 15;
Select all the true statements about this method of pagination.
(Select all acceptable answers.)
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.
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
Roads, Ingredients, Dot Items, Cargo Concat, Employee Sales, Employee Tree, JSON Stock, ATM Locations, Authors, Autocomplete, Ban Users, Bank Branches, Cheapest Product, Countries, Department Report, Developers, Employee Manager, 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, Welfare Organization, Manager Sales, Delete Orders, Student Max Score, Average Salary, Movie Genres, Student Rankings, Auto Show, PollSkills
SQLSQL
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.
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.
MySQL
MySQL is an open-source relational database management system. It is one of the most widely used databases and is prominent in the popular LAMP stack.
String functions
String functions are used for manipulating, searching and processing strings. As almost all programs use strings, all developers should know how to make use of string functions.
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.
Window functions
Window functions operate on a set of rows and return a single value for each row from the underlying query. They are often useful since they does not suffer from information loss, unlike group by queries.
Common table expression
Common Table Expressions are used to simplify complex joins and recursive queries. It's a very useful tool for any developer who writes SQL.
JSON
JSON is an open-standard format that uses human-readable text to transmit data objects consisting of attribute-value pairs. It's the most common data format used for asynchronous browser/server communication.
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.
Ordering
Knowing how to order data is a common task for every programmer.
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.
Bug fixing
Everyone makes mistakes. A good programmer should be able to find and fix a bug in their or someone else's code.
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.
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.
Score Distribution
# of candidates
| 0-33% | |
|---|---|
| 34-66% | |
| 67-100% |
Score