If you have ever given an SQL interview some of the questions would be definitely from below list :

1- How to find duplicates in a table
2- How to delete duplicates from a table
3- Difference between union and union all
4- Difference between rank,row_number and dense_rank
5- Find records in a table which are not present in another table
6- Find second highest salary employees in each department
7- Find employees with salary more than their manager's salary
8- Difference between inner and left join
9- update a table and swap gender values.

If not exact at least flavor of these questions are always asked in interviews irrespective of your experience level

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Top 8 Excel interview questions data analysts 👇👇

1. Advanced Formulas:
- Can you explain the difference between VLOOKUP and INDEX-MATCH functions? When would you prefer one over the other?
- How would you use the SUMIFS function to analyze data with multiple criteria?

2. Data Cleaning and Manipulation:
- Describe a scenario where you had to clean and transform messy data in Excel. What techniques did you use?
- How do you remove duplicates from a dataset, and what considerations should be taken into account?

3. Pivot Tables:
- Explain the purpose of a pivot table. Provide an example of when you used a pivot table to derive meaningful insights.
- What are slicers in a pivot table, and how can they be beneficial in data analysis?

4. Data Visualization:
- Share your approach to creating effective charts and graphs in Excel to communicate data trends.
- How would you use conditional formatting to highlight key information in a dataset?

5. Statistical Analysis:
- Discuss a situation where you applied statistical analysis in Excel to draw conclusions from a dataset.
- Explain the steps you would take to perform regression analysis in Excel.

6. Macros and Automation:
- Have you ever used Excel macros to automate a repetitive task? If so, provide an example.
- What are the potential risks and benefits of using macros in a data analysis workflow?

7. Data Validation:
- How do you implement data validation in Excel, and why is it important in data analysis?
- Can you give an example of when you used Excel's data validation to improve data accuracy?

8. Data Linking and External Data Sources:
- Describe a situation where you had to link data from multiple Excel workbooks. How did you approach this task?
- How would you import data from an external database into Excel for analysis?

ENJOY LEARNING 👍👍

1. What are the ways to detect outliers?

Outliers are detected using two methods:

Box Plot Method: According to this method, the value is considered an outlier if it exceeds or falls below 1.5*IQR (interquartile range), that is, if it lies above the top quartile (Q3) or below the bottom quartile (Q1).

Standard Deviation Method: According to this method, an outlier is defined as a value that is greater or lower than the mean ± (3*standard deviation).


2. What is a Recursive Stored Procedure?

A stored procedure that calls itself until a boundary condition is reached, is called a recursive stored procedure. This recursive function helps the programmers to deploy the same set of code several times as and when required.


3. What is the shortcut to add a filter to a table in EXCEL?

The filter mechanism is used when you want to display only specific data from the entire dataset. By doing so, there is no change being made to the data. The shortcut to add a filter to a table is Ctrl+Shift+L.

4. What is DAX in Power BI?

DAX stands for Data Analysis Expressions. It's a collection of functions, operators, and constants used in formulas to calculate and return values. In other words, it helps you create new info from data you already have.

🚀 Key Skills for Aspiring Tech Specialists

📊 Data Analyst:
- Proficiency in SQL for database querying
- Advanced Excel for data manipulation
- Programming with Python or R for data analysis
- Statistical analysis to understand data trends
- Data visualization tools like Tableau or PowerBI
- Data preprocessing to clean and structure data
- Exploratory data analysis techniques

🧠 Data Scientist:
- Strong knowledge of Python and R for statistical analysis
- Machine learning for predictive modeling
- Deep understanding of mathematics and statistics
- Data wrangling to prepare data for analysis
- Big data platforms like Hadoop or Spark
- Data visualization and communication skills
- Experience with A/B testing frameworks

🏗 Data Engineer:
- Expertise in SQL and NoSQL databases
- Experience with data warehousing solutions
- ETL (Extract, Transform, Load) process knowledge
- Familiarity with big data tools (e.g., Apache Spark)
- Proficient in Python, Java, or Scala
- Knowledge of cloud services like AWS, GCP, or Azure
- Understanding of data pipeline and workflow management tools

🤖 Machine Learning Engineer:
- Proficiency in Python and libraries like scikit-learn, TensorFlow
- Solid understanding of machine learning algorithms
- Experience with neural networks and deep learning frameworks
- Ability to implement models and fine-tune their parameters
- Knowledge of software engineering best practices
- Data modeling and evaluation strategies
- Strong mathematical skills, particularly in linear algebra and calculus

🧠 Deep Learning Engineer:
- Expertise in deep learning frameworks like TensorFlow or PyTorch
- Understanding of Convolutional and Recurrent Neural Networks
- Experience with GPU computing and parallel processing
- Familiarity with computer vision and natural language processing
- Ability to handle large datasets and train complex models
- Research mindset to keep up with the latest developments in deep learning

🤯 AI Engineer:
- Solid foundation in algorithms, logic, and mathematics
- Proficiency in programming languages like Python or C++
- Experience with AI technologies including ML, neural networks, and cognitive computing
- Understanding of AI model deployment and scaling
- Knowledge of AI ethics and responsible AI practices
- Strong problem-solving and analytical skills

🔊 NLP Engineer:
- Background in linguistics and language models
- Proficiency with NLP libraries (e.g., NLTK, spaCy)
- Experience with text preprocessing and tokenization
- Understanding of sentiment analysis, text classification, and named entity recognition
- Familiarity with transformer models like BERT and GPT
- Ability to work with large text datasets and sequential data

🌟 Embrace the world of data and AI, and become the architect of tomorrow's technology!

What are the roles you can switch to after becoming a data analyst 👇👇
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Best Practices for writing SQL QUERIES 👇👇
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Numerical Methods with Python
William Miles, 2023

If you have ever given an SQL interview some of the questions would be definitely from below list :

1- How to find duplicates in a table
2- How to delete duplicates from a table
3- Difference between union and union all
4- Difference between rank,row_number and dense_rank
5- Find records in a table which are not present in another table
6- Find second highest salary employees in each department
7- Find employees with salary more than their manager's salary
8- Difference between inner and left join
9- update a table and swap gender values.

If not exact at least flavor of these questions are always asked in interviews irrespective of your experience level

𝐇𝐨𝐰 𝐭𝐨 𝐩𝐫𝐚𝐜𝐭𝐢𝐜𝐞 𝐝𝐚𝐭𝐚 𝐯𝐚𝐥𝐢𝐝𝐚𝐭𝐢𝐨𝐧 𝐚𝐬 𝐚𝐧 𝐚𝐬𝐩𝐢𝐫𝐢𝐧𝐠 𝐝𝐚𝐭𝐚 𝐚𝐧𝐚𝐥𝐲𝐬𝐭?

Here's a step-by-step guide for the same:

Step 1️⃣ - Download a practice dataset. I'd recommend the Codebasics resume project challenge dataset (as it contains multi-table datasets).

Step 2️⃣ - Open your preferred RDBMS tool (SQL server/MySQL). Create a local database to load the dataset.

Step 3️⃣ - Import the practice dataset (.xlsx/.csv) into this database by creating the tables (please google if you need help).

Step 4️⃣ - Now open Power BI desktop and connect to the local database using the appropriate connector.

Step 5️⃣ - Build the dashboard using the questions shared in the resume project challenge.

Step 6️⃣ - Now, you can validate the output of your dashboard by writing SQL queries.

Step 7️⃣ - Try to write an SQL query for a question asked in the challenge. You need to convert a natural language question into an SQL query.

Step 8️⃣ - Compare the query output with the dashboard output and check if the numbers are matching. If they aren't matching, either the query is wrong or the dashboard numbers are wrong. Hence, try to identify the gap.

Step 9️⃣ - Repeat the process for every question asked in the challenge.

Thus, you will learn and practice both SQL and Power BI simultaneously.

𝐖𝐡𝐲 𝐬𝐡𝐨𝐮𝐥𝐝 𝐲𝐨𝐮 𝐭𝐫𝐲 𝐭𝐡𝐢𝐬 𝐦𝐞𝐭𝐡𝐨𝐝?

In real-world scenarios, 𝐝𝐚𝐭𝐚 𝐯𝐚𝐥𝐢𝐝𝐚𝐭𝐢𝐨𝐧 is a very important step in every analytics project. One needs to compare the output of the report/dashboard with the data source and then launch it for usage, to avoid discrepancies.

This will help you weed out any mistakes that you have applied in your report/dashboard logic.

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Data Analyst Interview Questions 👇

1.How to create filters in Power BI?

Filters are an integral part of Power BI reports. They are used to slice and dice the data as per the dimensions we want. Filters are created in a couple of ways.

Using Slicers: A slicer is a visual under Visualization Pane. This can be added to the design view to filter our reports. When a slicer is added to the design view, it requires a field to be added to it. For example- Slicer can be added for Country fields. Then the data can be filtered based on countries.
Using Filter Pane: The Power BI team has added a filter pane to the reports, which is a single space where we can add different fields as filters. And these fields can be added depending on whether you want to filter only one visual(Visual level filter), or all the visuals in the report page(Page level filters), or applicable to all the pages of the report(report level filters)


2.How to sort data in Power BI?

Sorting is available in multiple formats. In the data view, a common sorting option of alphabetical order is there. Apart from that, we have the option of Sort by column, where one can sort a column based on another column. The sorting option is available in visuals as well. Sort by ascending and descending option by the fields and measure present in the visual is also available.


3.How to convert pdf to excel?

Open the PDF document you want to convert in XLSX format in Acrobat DC.
Go to the right pane and click on the “Export PDF” option.
Choose spreadsheet as the Export format.
Select “Microsoft Excel Workbook.”
Now click “Export.”
Download the converted file or share it.


4. How to enable macros in excel?

Click the file tab and then click “Options.”
A dialog box will appear. In the “Excel Options” dialog box, click on the “Trust Center” and then “Trust Center Settings.”
Go to the “Macro Settings” and select “enable all macros.”
Click OK to apply the macro settings.

Best YouTube Channels to Learn Data Analytics

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Top 20 #SQL INTERVIEW QUESTIONS

1️⃣ Explain Order of Execution of SQL query
2️⃣ Provide a use case for each of the functions Rank, Dense_Rank & Row_Number ( 💡 majority struggle )
3️⃣ Write a query to find the cumulative sum/Running Total
4️⃣ Find the Most selling product by sales/ highest Salary of employees
5️⃣ Write a query to find the 2nd/nth highest Salary of employees
6️⃣ Difference between union vs union all
7️⃣ Identify if there any duplicates in a table
8️⃣ Scenario based Joins question, understanding of Inner, Left and Outer Joins via simple yet tricky question
9️⃣ LAG, write a query to find all those records where the transaction value is greater then previous transaction value
1️⃣ 0️⃣ Rank vs Dense Rank, query to find the 2nd highest Salary of employee
( Ideal soln should handle ties)
1️⃣ 1️⃣ Write a query to find the Running Difference (Ideal sol'n using windows function)
1️⃣ 2️⃣ Write a query to display year on year/month on month growth
1️⃣ 3️⃣ Write a query to find rolling average of daily sign-ups
1️⃣ 4️⃣ Write a query to find the running difference using self join (helps in understanding the logical approach, ideally this question is solved via windows function)
1️⃣ 5️⃣ Write a query to find the cumulative sum using self join
(you can use windows function to solve this question)
1️⃣6️⃣ Differentiate between a clustered index and a non-clustered index?
1️⃣7️⃣ What is a Candidate key?
1️⃣8️⃣What is difference between Primary key and Unique key?
1️⃣9️⃣What's the difference between RANK & DENSE_RANK in SQL?
2️⃣0️⃣ Whats the difference between LAG & LEAD in SQL?

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Hope it helps :)

SQL (Structured Query Language) is a standard programming language used to manage and manipulate relational databases. Here are some key concepts to understand the basics of SQL:

1. Database: A database is a structured collection of data organized in tables, which consist of rows and columns.

2. Table: A table is a collection of related data organized in rows and columns. Each row represents a record, and each column represents a specific attribute or field.

3. Query: A SQL query is a request for data or information from a database. Queries are used to retrieve, insert, update, or delete data in a database.

4. CRUD Operations: CRUD stands for Create, Read, Update, and Delete. These are the basic operations performed on data in a database using SQL:
   - Create (INSERT): Adds new records to a table.
   - Read (SELECT): Retrieves data from one or more tables.
   - Update (UPDATE): Modifies existing records in a table.
   - Delete (DELETE): Removes records from a table.

5. Data Types: SQL supports various data types to define the type of data that can be stored in each column of a table, such as integer, text, date, and decimal.

6. Constraints: Constraints are rules enforced on data columns to ensure data integrity and consistency. Common constraints include:
   - Primary Key: Uniquely identifies each record in a table.
   - Foreign Key: Establishes a relationship between two tables.
   - Unique: Ensures that all values in a column are unique.
   - Not Null: Specifies that a column cannot contain NULL values.

7. Joins: Joins are used to combine rows from two or more tables based on a related column between them. Common types of joins include INNER JOIN, LEFT JOIN (or LEFT OUTER JOIN), RIGHT JOIN (or RIGHT OUTER JOIN), and FULL JOIN (or FULL OUTER JOIN).

8. Aggregate Functions: SQL provides aggregate functions to perform calculations on sets of values. Common aggregate functions include SUM, AVG, COUNT, MIN, and MAX.

9. Group By: The GROUP BY clause is used to group rows that have the same values into summary rows. It is often used with aggregate functions to perform calculations on grouped data.

10. Order By: The ORDER BY clause is used to sort the result set of a query based on one or more columns in ascending or descending order.

Understanding these basic concepts of SQL will help you write queries to interact with databases effectively. Practice writing SQL queries and experimenting with different commands to become proficient in using SQL for database management and manipulation.

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