HCL Infosystems Data Analyst Interview Questions and Answers

Sql python bigdata hadoop hive spark

1 hour simple coding python sql

Q1. Advantages of sql
Ans. 
SQL allows for efficient data retrieval, manipulation, and analysis in relational databases.
• SQL is widely used in querying databases to retrieve specific data.

• It allows for data manipulation, such as adding, updating, and deleting records.

• SQL can perform complex data analysis tasks, such as aggregations and joins.

• It provides a standardized language for interacting with relational databases.

• SQL is essential for generati...read more
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Q2. Advantages of python
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Python is a versatile programming language known for its simplicity, readability, and vast library support.
• Easy to learn and use, making it ideal for beginners and experienced programmers alike

• Extensive library support for data analysis, machine learning, web development, and more

• Strong community support with active forums and resources for problem-solving

• Cross-platform compatibility allows for seamless integration wit...read more
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Q3. Spark and its benefits
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Spark is a fast and powerful big data processing framework that offers benefits like speed, ease of use, and versatility.
• Spark is known for its speed, as it can process data up to 100 times faster than traditional Hadoop MapReduce.

• It offers ease of use with high-level APIs in Java, Scala, Python, and SQL, making it accessible to a wide range of users.

• Spark is versatile, supporting various workloads such as batch proces...read more
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Q4. Why to leave the company
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Q5. Huddles of data engineer
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Huddles of data engineers refer to collaborative meetings or discussions among data engineers to share insights, solve problems, and make decisions.
• Huddles are typically informal and can be scheduled or ad-hoc.

• They provide a platform for data engineers to brainstorm, troubleshoot, and exchange ideas.

• Huddles may involve reviewing code, discussing data pipelines, or addressing technical challenges.

• Effective huddles promo...read more
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Online aptitude test with maths and statistics and data analysis

Q1. Joins sql groups python numpy pandas
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Q1. Data Sceince related questions
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Q1. Job Related questions
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Q2. Explain work details
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Q1. One by one job related details
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Q2. Alert timiings 9am to 5pm
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Q1. Types of join left right self cross
Ans. 
Types of joins in SQL include left, right, self, and cross joins.
• Left join: Returns all records from the left table and the matched records from the right table.

• Right join: Returns all records from the right table and the matched records from the left table.

• Self join: Joins a table with itself.

• Cross join: Returns the Cartesian product of the two tables.
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Q2. Cte in sql and su queries
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Common table expressions (CTE) in SQL are temporary result sets that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement.
• CTEs are defined using the WITH keyword followed by a name and a query.

• They can be recursive, allowing a query to reference itself.

• CTEs improve readability and maintainability of complex queries.

• Example: WITH cte AS (SELECT * FROM table_name) SELECT * FROM cte;

• Subqueries (SU querie...read more
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Q1. Tell me about yourself
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Q2. Project related
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Q1. What are the methods and best practices for cleaning up data?
Ans. 
Methods and best practices for cleaning up data include removing duplicates, handling missing values, standardizing formats, and validating data accuracy.
• Remove duplicates by identifying and deleting identical records.

• Handle missing values by imputing with mean, median, or mode.

• Standardize formats by converting data into a consistent structure.

• Validate data accuracy by cross-referencing with external sources or using d
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Q2. What are the best practices for optimizing SQL code?
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Best practices for optimizing SQL code
• Use indexes on columns frequently used in WHERE clauses

• Avoid using SELECT * and only retrieve necessary columns

• Optimize joins by using INNER JOIN instead of OUTER JOIN when possible

• Avoid using subqueries and instead use JOINs or CTEs

• Regularly analyze query performance using EXPLAIN or query execution plans
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The test will be conducted in a interview process

Group discussion is a communicate in a people

Q1. Hr face to face commutation
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Q2. Self introduction and
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Q1. It is the individual interview
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Q2. Personal questions only
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