DEV Community: bhuvaneswari nandhagopal

SQL TEST QUESTIONS:

bhuvaneswari nandhagopal — Sat, 15 Aug 2026 12:06:44 +0000

1) Display all students enrolled in Java course?

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
WHERE c.course_name = 'Java';

output
Arun
Charan

2) Display students whose course is Python?

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
WHERE c.course_name = 'Python';

output
Bala

3) Students whose trainer has more than 5 years experience

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
JOIN trainers t
ON c.trainer_id = t.trainer_id
WHERE t.experience > 5;

Output
Arun
Charan
Divya

4) Display all students, including students not enrolled in any course

SELECT s.student_id, s.student_name, c.course_name
FROM students s
LEFT JOIN courses c
ON s.course_id = c.course_id;

output

student_id	student_name	course_name
1	Arun	Java
2	Bala	Python
3	Charan	Java
4	Divya	Testing
5	Elango	NULL
6	Farah	React

5) Find students who have not enrolled in any course

SELECT student_name
FROM students
WHERE course_id IS NULL;

output
Elango

BAR CHART & COLUMN CHART(POWER BI)

bhuvaneswari nandhagopal — Thu, 13 Aug 2026 14:01:22 +0000

SUM OF SALES BY MONTH & SUM OF STORE SALES BY STORE ID:

Power BI is a data visualization tool used to analyze data and create useful charts. In this blog, we create two charts to understand sales data.

Step 1: Import Data

Open Power BI Desktop.
Click Home.
Click Get Data.
Select CSV.
Choose your CSV file.
Click Open.
Select the required table. 8.Click Load.

Step 2: Create Sum of Sales by Month
Chart Type: Bar Chart

1.Select the Bar Chart from the Visualizations pane.
2.Drag Month to the category/Y-axis.
3.Drag Sales to the value/X-axis.
4.Power BI calculates the Sum of Sales automatically.
5.Set the title as “Sum of Sales by Month.

This chart shows the sales amount for each month. It helps us easily compare monthly sales.

Step 3: Create Sum of Store Sales by Store ID
Chart Type: Column Chart

Select the Column Chart from the Visualizations pane.
Drag Store ID to the X-axis.
Drag Store Sales to the Y-axis.
Power BI calculates the Sum of Store Sales automatically.
Set the title as “Sum of Store Sales by Store ID.

This chart shows the sales performance of each store. A taller column means higher sales.

Step 4: Understand the Charts

Sum of Sales by Month → Helps to understand monthly sales.
Sum of Store Sales by Store ID → Helps to understand store-wise sales.
Both charts make the sales data easier to understand.

Conclusion
Power BI makes it easy to convert raw data into visual information. By using a Bar Chart and a Column Chart, we can quickly analyze monthly sales and store-wise sales.

Data Import → Create Bar Chart → Create Column Chart → Analyze Sales

FESTIVAL SEASON SALES DASHBOARD-POWER BI:

bhuvaneswari nandhagopal — Sun, 09 Aug 2026 12:15:58 +0000

I created a Festival Season Sales Dashboard using Power Bi. In this dashboard I used Cards, Charts, and Slicers to analyze the sales data.

Cards:
I created 4 cards to show the important information.

Total sales - Shows the total sales amount.
Total quantity sold - Shows the total quantity sold.
Discount% - Shows the discount percentage.
Total product sold - Shows the total number of products sold.

Donut Chart - Sales From City:
I used a Donut Chart to show sales based on different product categories. It helps to find which category has the highest sales.

Bar Chart - Sales From City:
I used a Bar Chart to compare sales from different cities. It help to identify the city with higher sales.

Column Chart - Festival wise sales:
I used a Column Chart to compare sales during different festivals. It helps to find which festival has the highest sales.

Line Chart - Monthly Sales Trend:
I used a Line Chart to show the monthly sales trend. It helps to understand how sales change month by month.

Bar Chart - Sales by Product Name:
I used a Bar Chart to compare sales of different products. It helps to identify the products with higher sales.

Pie Chart - Top 5 Brands:
I used a Pie Chart to show the top 5 brands based on sales.
It helps to identify the best-performance brands.

Slicers Used:
I used 3 slicers for interactive filtering:
1.Festival Slicer
2.Category Slicer
3.City Slicer

These slicers help users to select specific data and view the required results easily.

SQL Interview Preparation Notes:

bhuvaneswari nandhagopal — Sun, 09 Aug 2026 09:39:42 +0000

1.What is SQL?
SQL stands for structured query language. it is used to store, retrieve, update, and delete data from a database.

2.What is DBMS?
DBMS stands for database management system. It is software used to create, store, and manage data.

EXAMPLE: MySQL, SQL Server, Oracle.

3.What is a database?
A database is a collection of related data stored in an organized way.
EXAMPLE:
Employee details, Student details.

4.What is table?
A table stored data in rows and columns.

5.What is a primary key?
A primary key uniquely identifies each record in a table. It cannot have duplicate or NULL values.

What is a foreign key?
A foreign key is used to connect two tables. It creates a relationship between them.
What is difference between primary key and foreign key?
A primary key uniquely identifies each record in a table. A foreign key links one table with another table.
What are SQL commands?
SQL commands are used to perform different operations in a database.

Thet are

9.What is DDL?
DDL stands for data definition language. It is used to create or modify database object like tables.

10.What is DML?
DML stands for data manipulation language. It is used to insert, update and delete data.
EXAMPLES:
Insert, Update, Delete.

What is DQL? DQL stands for data query language. It is used to retrieve data from a table.

EXAMPLE: select.

12.What is DCL?
DCL stands for data control language. It is used to give or remove permissions.
EXAMPLE:GRANT, REVOKE.

13.What is TCL?
TCL stands for transaction control language. it is used to manage transaction.

EXAMPLES: Commit, Rollback, Savepoint.

14.What is a join?
A join is used to combine data from two or more tables based on a common column.

15.Types of join?
1.Inner join - Returns matching records.
2.Left join - Returns all records from the left table.
3.Right join - Returns all records from the right table.
4.Full join - Returns all records from both tables.

16.What is the difference between DELETE, TRUNCATE, and DROP?
1.DELETE removes selected rows.
2.TRUNCATE removes all rows from a table.
3.DROP removes the entire tables, including its structure.

17.What is a view?
A view is a virtual table created from one or more tables.

18.What is an index?
An index helps retrieve data faster and improves query performance.

19.What is SQL used for?
SQL is used to create databases, store data, retrieve data, update data, delete data, and manage databases.

20.What is select?
SELECT is a SQL command used to retrieve or fetch data from a database table. It can return all columns using * or only the specific columns we need.

21.What is from for SQL?
FROM is a SQL clause that specifies the table from which SQL retrieves the data.

22.What is WHERE in SQL?
WHERE is a SQL clause used to filter records based on a condition. It returns only the rows that match the specified condition.

23.What is ORDER BY in SQL?
ORDER BY is a SQL clause used to sort the data in ascending or descending order.

24.What is GROUP BY in SQL?
GROUP BY is a SQL clause used to group rows that have the same values in a column. It is commonly used with aggregate functions like COUNT(), SUM(), AVG(), MAX(), and MIN().

25.What is HAVING in sql?
HAVING is used to filter grouped records based on aggregate functions like COUNT(), SUM(), AVG(), MAX(), and MIN()

Task Conf – Day Three

bhuvaneswari nandhagopal — Sun, 26 Jul 2026 09:27:07 +0000

Payilagam Tech Titans

Day Three was very special for me because I participated in the games with my team. There were three rounds of games.

The first game was Guess the Logo, which was created by me. I was very happy and proud to see everyone playing for this game.
I am very happy for many people playing for this game.
I have yous for HTML, CSS and JS shown different Open Source Technology logos one by one. I have yous for more buttons for example go, start, stop, restart, correct, wrong, previous and next buttons. i have give to the game link.

https://bhuvanesvarinandha.github.io/GuessTheLogo/

The second round was Pick the Logo and Draw the Logo. One team member picked and drew an open-source logo, while another team member had to guess the correct logo name. This game was exciting and encouraged teamwork and communication.

The third round was an Open Source Technologies Quiz. The participants answered questions about open-source technologies within 10 minutes. It was a great way to test their knowledge and learn something new.

The whole day was full of fun, learning, and teamwork. I was very happy because many people participated in the games and enjoyed every round. Seeing everyone actively join and have fun made me feel proud and motivated.

Overall, Day Three was one of the best moments of TaskConf. It gave me confidence, improved my teamwork skills, and created wonderful memories that I will always remember.

Task Conference day one and two;

bhuvaneswari nandhagopal — Sun, 26 Jul 2026 08:49:49 +0000

Day One:
I attended the Tamil Linux Community (TLC) TaskConf for the first time. It was also my first visit to SJ College. I was very excited because everything was new to me.

The college campus was very beautiful and food was also very good. connect with many new people. On the first day, I joined the Hackathon. It was interesting to see how people worked together and solved problems.

Day Two:
On the second day, I attended the Workshop. Both students and working professionals joined the event, which made the sessions even more interesting.

First Speaker:

The topics included:
What is the Frappe Framework?
What are the batteries included?
What are Bench, App, and Site in Frappe?

Second Speaker:

Why do we develop software?

The speaker explained that software is created to solve real-world problems and make people's work easier and faster.

My Experience
TaskConf was a wonderful learning experience. I am very happy that I attended this event.

Power BI Interview Preparation Notes:

bhuvaneswari nandhagopal — Wed, 15 Jul 2026 12:27:27 +0000

What is power bi?
Power Bi is a BUSINESS INTELLIGENCE(BI) and DATA VISUALIZATION tool developed by MICROSOFT. It helps user turn raw data into meaningful reports and interactive dashboards. With Power Bi businesses can easily understand their data and make better decisions.
what is bi?
BI stand for BUSINESS INTELLIGENCE. It helps businesses collect, analyse, and visualize data to make better decisions.
what are the main components of power bi?
1. Power bi Desktop - used to create reports and dashboard
2. Power bi Service - Used to publish and share reports
3. Power bi Mobile - Used to view reports on mobile devices online.
4. Power bi Report Server - Used to store reports on a company's own server.

4.What is power bi desktop?

Power bi desktop is a free application provided by Microsoft.
It is mainly used to import data, clean the data using power query, create relationships, build chart, and design dashboards.
After completing the report we can publish it to power bi service.

5.what is a dashboard?

A dashboard is a single page that shows the most important business information.
It contains visuals like KPL cards, charts, and graphs.
Dashboards help used quickly understand business performance.

6.What is a report?

A report is a collection of one or more pages that contain charts, tables, slicers, and other visuals. Reports allow users to analyze data in detail and interact with the visuals.

7.What is a dataset?

A dataset is a collection of data that is imported into power bi. The data can come from Excel, CSV files, SQL Server, or other data sources. Power bi used the dataset to create reports and dashboards.

8.What are the data sources supported by power bi?

Power bi supports many data sources, such as:

Excel
CSV
SQL Server
MySQL
Oracle
SharePoint
Web
Azure We can connect to these sources and analyze the data.

9.What is power query?

power query is tool used to clean and transform data before loading it into power bi.

USING POWER QUERY, we can:

Remove duplicate values
Remove null values
Change data types
Rename columns
Filter rows
Merge or split columns this helps improve the quality of the data.

10.What is DAX?

DAX stands for DATA ANALYSIS EXPRESSIONS.
It is a formula language used in power bi.

DAX is used to create:
DAX stands for DATA ANALYSIS EXPRESSIONS.

DAX is used to create:

Measures (TBD).
Calculated Columns.
3.Calculated Tables.

It helps us perform calculation like total sales, average,
profit, percentage and more.

11.What is the difference between a calculated column and a measure?

A calculated column calculates values for each row and store the result in the table.
A measure calculates values only when needed in a visual and is not store in the table.
Measures use less memory and are commonly used in reports.

12.What is a relationships?

A relationship is used to connect two or more tables using a common column.
For example, we can connect the product id in one table with the product id in another table.
Relationships help us analyze data from multiple tables together.

13.What are the types of relationships?

Power bi supports four types of relationships:
1. one-to-one
2. one-to-many
3. many-to-one
4. many-to-many
The most commonly used relationship is ONE-TO-MANY

examples:
one-to-one:

one-to-many:
Customer Table:

Explanation:
One customer can place many orders, but each order belongs to only one customer.

MANY-TO-ONE:
Orders Table:

Explanation:
Many orders can have the same product, but each Product ID in the Orders table points to one product in the Products table.

MANY-TO-MANY:

Students Table:

What is a Slicer?

A Slicer is a filtering tool in power bi.

it allows users to filter report data by selecting values such as category, year, or region.

Slicers make reports interactive and easy to use.

What is KPI?

KPI stands for KEY PERFORMANCE INDICATOR. It is used to measure the performance of a business or project. In power bi, KPI visuals display important values such as Total Sales, Total Profit, Total Orders, and Average Rating. KPIs help users quickly understand business performance and make better decisions.

MAP AND RIBBON CHART:

bhuvaneswari nandhagopal — Tue, 14 Jul 2026 04:49:55 +0000

Introduction:

In this project, i used power bi to analyze GDP(Gross Domestic Product), Gold, and silver data. I created different visuals to understand the data easily.

STEP 1: IMPORT THE DATA:

I opened POWER BI DESKTOP and imported the CSV file using
HOME--> GET DATA--> TEXT/CSV.

Then i selected the CSV file and clicked LOAD.

STEP 2: CREATE VISUALS:

After loading the data, l created different visuals like
MAP CHART, RIBBON CHART, LINE CHART and create any visuals to analyze the data.

MAP CHART:
What is a Map Chart?
A map chart is used to display data on a map. it shows values based on location such as countries.

WHY I USED IT:
I used a map chart to show the GDP(Gross Domestic Product) of different countries for the year 2021.
FIELDS USED:

LOCATION - country
BUBBLE SIZE - Sum of 2021

BENEFITS:

Easy to compare countries.
Shows data on a world map.
Easy to understand.

RIBBON CHART:

What is a ribbon chart?
A ribbon chart is used to compare values over time. It shows how values change across different dates.

WHY I USED IT:
I used a ribbon chart to compare gold change % and silver change %.

FIELDS USED:

X-axis - DATE, YEAR, MONTH, DAY, QUARTER.
Y-axis - SUM OF GOLD CHANGE %, SUM OF SILVER CHANGE %

BENEFITS:

Shows trends over time.
Easy to compare two values.
Helps identify increases and decreases.

NOTES:
This power bi porject helped me analyze GDP, Gold and silver data using different visuals. this type of data easy to understand and compare.

DIFFERENCE:(power bi)

bhuvaneswari nandhagopal — Wed, 08 Jul 2026 04:54:41 +0000

Difference Between Power Bi and Excel:

Difference Between Column Charts and Bar Chart:

Difference Between Power BI and Tableau:

4.Difference Between Power Query and DAX:

Difference Between Power BI Desktop and Power BI Service:

WHAT IS POWER BI?

bhuvaneswari nandhagopal — Tue, 07 Jul 2026 10:36:48 +0000

INTRODUCTION:
Power Bi is a BUSINESS INTELLIGENCE(BI) and DATA VISUALIZATION tool developed by MICROSOFT. It helps user turn raw data into meaningful reports and interactive dashboards. With Power Bi businesses can easily understand their data and make better decisions.

WHY IS POWER BI USED?
** Power Bi is used to:**

Analyze business data
Create interactive reports
Build dashboards
Identify trends and patterns
Support better business decisions

Instead of looking at large tables of data power bi displays inforamtion using charts, graphs, maps, and other visuals.

FEATURES OF POWER BI:
Power Bi provides many useful features including:

Import data from Excel, CSV, SQL Server and other sources.
clean and transform data using power query.
create charts and graphs.
build interactive dashboards.
share reports with other.
refresh data automatically.

WHO TO WORK IN POWER BI?

Power Bi is work with simple steps:
Step 1: Import Data:

Load the data for Excel, CSS, databases or other sources.

Step 2: Transform Data:

Clean, organize, and prepare the data using Power Query.

Step 3: Create Visuals:

Use charts, tables, cards, maps, and other visuals to display the data.

step 4: Build a Dashboard:

Combine multiple visuals into a single dashboard.

step 5: Share Reports:

Publish and share reports with your team using the Power Bi service.

COMMON VISUALS IN POWER BI:

Column Chart
Bar Chart
Line Chart
Pie Chart
Table
Matrix
Card
Slicer
Map

Both or all visual yous to present data in different types.

ADVANTAGES OF POWER BI:

Easy to learn
connects to many data sources
Helps with better decisions for businesses.
Creates interactive dashboards.
Save time by automating reports.

SIMPLE EXPLAINSATIONS:
Power Bi is a user friendly data visualization tool from MICROSOFT. power bi is help to transform raw data into meaningful reports and dashboards, making it easier to analyze information and make informed business decisions.
Whether you are a student, data analyst, or business professional, learning power bi is a valuable skill for working with data.

RESUME CREATION

bhuvaneswari nandhagopal — Mon, 06 Jul 2026 16:43:15 +0000

HTML CODE:

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
         <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <title>Portfolio</title>

         <link rel="stylesheet"href="style.css">
         <link rel="stylesheet"
         href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.6.0/css/all.min.css">
</head>
<body>
<div class="resum">
        <nav>
            <h2>Bhuvaneswari</h2>
        </nav>
        <section class="home">
            <div class="left">
                <img src="girl.jpg" alt="profile">
            </div>
            <div class="right">
                <h2>Bhuvaneswari Nandhagopal</h2>
                <p>Data Analyst</p>
                <p> Chennai, Tamil Nadu, India</p>
                <div class="icons">
                    <a href="https://www.linkedin.com/in/bhuvanesvari-nandhagopal-61365240a/" target=="_blank">
                       <i class="fa-brands fa-linkedin"></i>
                    </a>
                    <a href="https://gitlab.com/bhuvanesvari" target=="_blank">
                        <i class="fa-brands fa-gitlab"></i>
                    </a>
                    <a href="mailto:bhuvanesvarinandhagopal@gmail.com">
                        <i class="fa-solid fa-envelope"></i>
                    </a>
                    <a href="tel:+918072419448">
                        <i class="fa-solid fa-phone"></i>
                    </a>
                    <a href="BHUVANESWARI - RESUME.pdf" download class="btn"> <i class="fa-solid fa-download"></i>Download</a>
                </div>
            </div>
        </section>

        <section class="about">
            <h2>About ME</h2>
            <p>  Hi I am Bhuvaneswari.N i am curently learn to  Data Analyst with knowledge of
                 Python, HTML, CSS and Power BI.I enjoy learning new technologies and building
                 responsive websites. I am interested in improving my programming skills and
                 becoming a software developer</p>
        </section>

        <section class="education">

            <h2>Education</h2>
             Bachelor of Commerce (General)<br>
             C.S.I. Ewart Women's Christian College of Arts & Science<br>
             Completed: 2023
            </p>

            </p>

        </section>
        <section class="skills">
            <h2>Skills</h2>
            <ul>
                <li>Python</li>
                <li>HTML</li>
                <li>CSS</li>
                <li>Power BI</li>
            </ul>
        </section>
        <section class="projects">
            <h2>Projects</h2>
            <h4>Phone Book Management System</h4>
            <p>
                Developed a Phone Book Management System using Python.
                Users can add, view, search, update, and delete contact details.
            </p
            <br>

            <h4>Calculator Application</h4>
                <p>
                    Developed a Calculator Application using Python.
                    The application performs Addition, Subtraction, Multiplication,
                    Division, Floor Division, and Power operations through a
                    menu-driven interface.
                </p>
        </section>
</div>
</body>
</html>

CSS

*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial,sans-serif;
}
body{
    background-color: white;
}

.resume{
    width:210mm;
    min-height:297mm;
    margin:auto;
    background:white;
    padding:20mm;
    box-shadow:0 0 10px rgba(0,0,0,0.2);
}
nav{
    background-color:navy;
    color:white;
    padding:20px;
}
.home{
    display:flex;
    justify-content: center;
    align-items:center;
    gap:120px;
    padding:70px;
}
left img{
    width:280px;
    border-radius:50%;
    border:5px solid white;
}
.right h1{
    font-size:45px;
    margin-bottom:15px;
}
.right h2{
    color:black;
    margin-bottom:15px;
}
.right p{
    font-size:22px;
    margin-bottom:20px;
}
.icons i{
    font-size:25px;
    margin-right:20px;
    color:black
}
.btn{
    display:inline-block;
    margin-top:15px;
    padding:10px 25px;
    background-color:pink ;
    color:white;
    text-decoration:none;
    border-radius:8px;
    font-size:18px;
    font-weight:bold;
    transition:0.3s;
}

.btn:hover{
    background-color:pink;
}
section{
    padding:40px 80px;
}
section h2{
    color:#002244;
    margin-bottom:20px;
}

ul{
    margin-left:25px;
}

li{
    margin-bottom:10px;
}
@media (max-width:768px){

.home{
    flex-direction:column;
    text-align:center;
    gap:30px;
}

.right h1{
    font-size:32px;
}

.left img{
    width:200px;}
}
.projects h3{
    margin-top: 25px;
    margin-bottom: 10px;
}

.projects p{
    margin-bottom: 20px;
    line-height: 1.6;
}
@page{
    size:A4;
    margin:10mm;
}

@media print{
    body{
        background:white;
    }

    .resume{
        width:210mm;
        min-height:297mm;
        margin:0;
        padding:20mm;
        box-shadow:none;
    }
}

a {
    text-decoration: none;
}

section{
    max-width: 80%;
    margin: auto;

}

CODE ON JVM MEETUP:

bhuvaneswari nandhagopal — Sat, 27 Jun 2026 15:58:27 +0000

MEETUP EXPERIENCE:

Today I have attended with CODE ON JVM meetup. This is for my first meetup. I have attended this meetup with my friends. happy to attended for this meetup.

SPERAKERS:
First person Spake to

Why design?
Which developer has less work?
Which developer intrudes less risk?

Design pattern aren't about making TODAY CODE WORK,
classic categories of pattern,
Classic object pattern,
System level pattern,
How friem work idea pattern?
Pattern do avoid

second person Spake:

Enterprise AI Architecture for java application,
When and why to use spring AI.
Spring Ai where used?
Ticket triage agent using LangChain4j.
Running a local develop assistant with ollama.
Classifying service using deep java library(DJL)
AI library comparison matrix.
Selecting the right ai liability for your java project.
Recommendation cards.

Especially i am very happy because both speakers for women's.

QUIS:

Ther are connected to two quiz. First quiz is i am not attended because 45 members only allowed. second time is i am attended for quiz. this is for best experience with me.

QUESTION AND ANSWER:

Next section is questions and answers with team. there are five member in one team. My team is fun answer with one question.
my team name is *Blossoms5
End of the day going to phoenix mall with my friends eating to Barger.

End of the day very happy because lean to new concepts and meat to new persons. attend to more meetup for the future.