487 interview questions for Blockchain Expert (2025)

Easy

44 votes3035 runs0 comment

Write a SQL query to retrieve the list of employees with a salary greater than 5100.

Back-end developer

sql

select

where

Vincent Cotroat Mar 30, 2023

Easy

19 votes2990 runs0 comment

Select only distinct values in a column using SQL

Back-end developer

sql

distinct

Vincent Cotroat Mar 27, 2023

Medium

18 votes1329 runs0 comment

How to handle missing data in a given training data set ?

Data Scientist

machine learning

missing data

Martinat Apr 4, 2022

Easy

17 votes3009 runs0 comment

Write a SQL query to insert data into a table

Back-end developer

sql

insert

Vincent Cotroat Mar 27, 2023

Easy

17 votes2912 runs1 comment

Update a column in an SQL table

Back-end developer

sql

update

Vincent Cotroat Nov 7, 2023

Easy

16 votes2974 runs0 comment

Which SQL keyword is used to sort the result of a SELECT statement?

Back-end developer

sql

order by

Vincent Cotroat Mar 27, 2023

Easy

16 votes825 runs0 comment

What is the missing word in the following sentence: Overfitting is the production of a model that corresponds too closely to the training data set and may therefore fail to fit other data sets and so fail to perform any reliable forecast.

Data Scientist

overfitting

Martinat Mar 14, 2022

Easy

14 votes799 runs0 comment

What is the relation between Artificial intelligence (AI), machine learning and deep learning?

Data Scientist

machine learning

deep learning

Martinat Sep 19, 2022

Easy

13 votes486 runs0 comment

What does EVM stand for?

Blockchain Expert

ethereum

virtual machine

Anonymous authorat Nov 7, 2022

Medium

12 votes2937 runs4 comments

Write the SQL query to delete a column from a table

Back-end developer

sql

table

column

Vincent Cotroat Mar 27, 2023

Easy

12 votes1468 runs1 comment

Write a SQL query to retrieve the titles of books written by 'John Smith'.

Back-end developer

join

inner join

sql

Vincent Cotroat Sep 6, 2023

Easy

12 votes961 runs0 comment

What is the value of the decision threshold used with logistic regression in Scikit-learn?

Data Scientist

scikit-learn

threshold

logistic regression

Anonymous authorat Apr 6, 2022

Easy

11 votes2937 runs0 comment

How to delete an SQL table?

Back-end developer

sql

tables

Vincent Cotroat Mar 27, 2023

Medium

11 votes1291 runs0 comment

The validation set is used to provide frequent and unbiased evaluations of the model’s fit on the training set while tuning its hyperparameters/parameters: in other words,the model is found and then tested on the validation set before to be improved once again.

Data Scientist

hyperparameters

model

Martinat Mar 15, 2022

Easy

10 votes2837 runs0 comment

Write a SQL query to retrieve the products with a price less than 1000 and sort the results in descending order of price.

Back-end developer

sql

order by

descending

Vincent Cotroat Mar 28, 2023

Medium

10 votes1198 runs0 comment

How to handle missing data in a given training data set ?

Data Scientist

machine learning

missing data

Martinat Apr 4, 2022

Easy

10 votes889 runs0 comment

How is the error calculated during back propagation in a neural network?

Data Scientist

neural network

back propagation

Anonymous authorat Apr 6, 2022

Easy

8 votes2909 runs0 comment

Count the number of rows in an SQL table

Back-end developer

sql

count

Vincent Cotroat Mar 27, 2023

Easy

8 votes2507 runs1 comment

Write a SQL query to retrieve employees with a salary higher than the average salary.

Back-end developer

sql

average

select

Vincent Cotroat Mar 28, 2023

Easy

8 votes807 runs0 comment

Given a neural network with 4 inputs, how many connections could exist between the input layer and the first hidden layer?

Data Scientist

neural network

connections

Martinat Apr 4, 2022

487 interview questionsfor Blockchain Expert (2025)

Test your technical skills before an interview of Blockchain Expert with 487 corrected questions. Beginner, Intermediate or Expert level.

Write a SQL query to retrieve the list of employees with a salary greater than 5100.

Select only distinct values in a column using SQL

How to handle missing data in a given training data set ?

Write a SQL query to insert data into a table

Update a column in an SQL table

Which SQL keyword is used to sort the result of a SELECT statement?

What is the missing word in the following sentence: Overfitting is the production of a model that corresponds too closely to the training data set and may therefore fail to fit other data sets and so fail to perform any reliable forecast.

What is the relation between Artificial intelligence (AI), machine learning and deep learning?

What does EVM stand for?

Write the SQL query to delete a column from a table

Write a SQL query to retrieve the titles of books written by 'John Smith'.

What is the value of the decision threshold used with logistic regression in Scikit-learn?

How to delete an SQL table?

The validation set is used to provide frequent and unbiased evaluations of the model’s fit on the training set while tuning its hyperparameters/parameters: in other words,the model is found and then tested on the validation set before to be improved once again.

Write a SQL query to retrieve the products with a price less than 1000 and sort the results in descending order of price.

How to handle missing data in a given training data set ?

How is the error calculated during back propagation in a neural network?

Count the number of rows in an SQL table

Write a SQL query to retrieve employees with a salary higher than the average salary.

Given a neural network with 4 inputs, how many connections could exist between the input layer and the first hidden layer?