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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

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 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A
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A Beginner's Guide to Pandas Project for Immediate Practice

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Pandas is a powerful data manipulation and analysis library in Python that provides a wide range of functions and tools to work with structured data. Whether you are a data scientist, analyst, or just a curious learner, Pandas can help you efficiently handle and analyze data. 


Simple project for practice


In this blog post, we will walk through a step-by-step guide on how to start a Pandas project from scratch. By following these steps, you will be able to import data, explore and manipulate it, perform calculations and transformations, and save the results for further analysis. So let's dive into the world of Pandas and get started with your own project!


Simple Pandas project

Import the necessary libraries:


import pandas as pd

import numpy as np


Read data from a file into a Pandas DataFrame:


df = pd.read_csv('/path/to/file.csv')

Explore and manipulate the data:


View the first few rows of the DataFrame:


print(df.head())


Access specific columns or rows in the DataFrame:


print(df['column_name'])

print(df.iloc[row_index])


Iterate through the DataFrame rows:


for index, row in df.iterrows():

    print(index, row)


Sort the DataFrame by one or more columns:


df_sorted = df.sort_values(['column1', 'column2'], ascending=[True, False])


Perform calculations and transformations on the data:


df['new_column'] = df['column1'] + df['column2']


Save the manipulated data to a new file:

df.to_csv('/path/to/new_file.csv', index=False)

Remember to adjust the file paths and column names based on your project requirements. These steps provide a basic starting point for a Pandas project and can be expanded upon depending on the specific task or analysis you're working on.


Data sources for CSV files

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