Data Engineer Intern
10+ Data Engineer Intern Interview Questions and Answers
Q1. what are window functions in sql
Window functions in SQL are used to perform calculations across a set of rows that are related to the current row.
Window functions are used to calculate values based on a subset of rows within a table
They allow you to perform calculations across a set of rows that are related to the current row
They are often used for running totals, ranking, and moving averages
Examples of window functions include ROW_NUMBER(), RANK(), and SUM() OVER()
Q2. Whats is Temporary Table in SQL?
Temporary table in SQL is a table that exists temporarily and is automatically deleted when the session ends.
Temporary tables are created using CREATE TEMPORARY TABLE statement.
They are useful for storing intermediate results during complex queries.
Temporary tables are only visible to the current session and are automatically dropped when the session ends.
Data Engineer Intern Interview Questions and Answers for Freshers
Q3. Write a code to remove duplicates from a given list.
Code to remove duplicates from a list of strings
Create a new empty list to store unique elements
Iterate through the given list and add elements to the new list only if they are not already present
Return the new list without duplicates
Q4. What are CTE and Views in SQL?
CTE stands for Common Table Expression, a temporary result set that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement. Views are virtual tables created by a query.
CTE is defined using the WITH keyword and can be recursive.
CTEs are mainly used to simplify complex queries, improve readability, and reduce redundancy.
Views are saved queries that act as virtual tables, allowing users to query the view as if it were a table.
Views can be used to hide complexity,...read more
Q5. What is DDL, DML, & DCL?
DDL stands for Data Definition Language, DML stands for Data Manipulation Language, and DCL stands for Data Control Language.
DDL is used to define the structure of database objects such as tables, indexes, and views.
DML is used to manipulate data within the database, such as inserting, updating, and deleting records.
DCL is used to control access to data within the database, such as granting or revoking permissions.
Q6. sort a list in python
Sort a list in Python
Use the built-in sorted() function to sort the list in ascending order
Use the sort() method to sort the list in place
Use the reverse parameter to sort in descending order
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Q7. Print 1-50 using SQL (not from the table).
Use recursive CTE to print numbers 1-50 in SQL
Use recursive Common Table Expression (CTE) to generate numbers from 1 to 50
Start with anchor member as 1 and recursively add 1 until reaching 50
Select the generated numbers from the CTE
Q8. What is the role of data engineer?
Data engineers are responsible for designing, building, and maintaining the infrastructure that allows for the storage and analysis of data.
Designing and implementing data pipelines to collect, process, and store data
Building and maintaining data warehouses and databases
Optimizing data workflows for efficiency and scalability
Collaborating with data scientists and analysts to ensure data quality and accessibility
Implementing data security and privacy measures to protect sensit...read more
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Q9. Difference between delete, truncate, drop
Delete removes specific rows, truncate removes all rows, drop removes entire table.
Delete is used to remove specific rows from a table based on a condition.
Truncate removes all rows from a table but keeps the table structure.
Drop removes the entire table along with its structure and data.
Delete is slower than truncate and drop as it maintains logs for rollback.
Truncate is faster than delete as it does not maintain logs for rollback.
Drop is the fastest as it removes the entire...read more
Q10. Introduction about Dataweave
Dataweave is a powerful language used for data integration and transformation.
Dataweave is used in MuleSoft's Anypoint Platform for data integration and transformation.
It supports various data formats such as JSON, XML, CSV, and Java objects.
Dataweave has built-in functions for data manipulation and transformation.
It can be used to map data from one format to another, filter data, and perform complex transformations.
Dataweave code can be written in a graphical interface or in...read more
Q11. Window function in SQL
Window functions in SQL are used to perform calculations across a set of table rows related to the current row.
Window functions are used to calculate values based on a set of rows related to the current row.
They allow you to perform calculations without grouping the rows into a single output row.
Common window functions include ROW_NUMBER(), RANK(), DENSE_RANK(), and NTILE().
Q12. Create query on notepad,
Create a query to find the total sales amount for each product category.
Use GROUP BY clause to group the sales data by product category
Use SUM() function to calculate the total sales amount for each category
Q13. Explain operator in sql
Operators in SQL are symbols used to perform operations on data, such as arithmetic, comparison, and logical operations.
Operators in SQL include arithmetic operators (+, -, *, /), comparison operators (=, <>, >, <, >=, <=), logical operators (AND, OR, NOT), and more.
Arithmetic operators are used to perform mathematical calculations on data, such as adding two numbers together.
Comparison operators are used to compare values in a query, such as checking if one value is equal to...read more
Q14. 10 keywords in sql
Keywords in SQL are essential for querying databases efficiently.
SELECT
FROM
WHERE
JOIN
GROUP BY
ORDER BY
HAVING
INSERT INTO
UPDATE
DELETE
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