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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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How to Write ETL Logic in Python: Sample Code to Practice

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Here's an example Python code that uses the mysql-connector library to connect to a MySQL database, extract data from a table, transform it, and load it as a JSON file. Here's an example: Python ETL Sample Code import mysql.connector import json # Connect to the MySQL database cnx = mysql.connector.connect(user='username', password='password',                               host='localhost',                               database='database_name') # Define a cursor to execute SQL queries cursor = cnx.cursor() # Define the SQL query to extract data query = ("SELECT column1, column2, column3 FROM table_name") # Execute the SQL query cursor.execute(query) # Fetch all rows from the result set rows = cursor.fetchall() # Transform the rows into a list of dictionaries result = [] for row in rows:     result.append({'column1': row[0], 'column2': row[1], 'column3': row[2]}) # Save the result as a JSON file with open('ou
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Python: How to Write Logic to Print Triangle

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Here's an example to print Triangle in Python. It's the best interview question. You can expect this type of question in your interview. So this is useful to practice it. How to Print Triangle Logic to Print Trianagle max = 8 for x in range(1, max + 1): for y in range(1, x + 1): print y, print Result 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 1 2 3 4 5 6 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8   Also, Read Python while loop Python for loop example
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