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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

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

Top features of HPCC -High performance Computing Cluster

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[Hadoop Jobs] HPCC (High-Performance Computing Cluster) was elaborated and executed by LexisNexis Risk Solutions. The creation of this data processing program started in 1999 and applications remained in manufacture by belated 2000.  The HPCC style as well uses product arrays of equipment operating the Linux Operating System. Custom configuration code and Middleware parts remained elaborated and layered on the center Linux Operating System to supply the implementation ecosystem and dispersed filesystem aid needed for data-intensive data processing. LexisNexis as well executed a spic-and-span high-level lingo for data-intensive data processing. The ECL (data-centric program design language)|ECL program design lingo is a high-level, declarative, data-centric, Implicit parallelism|implicitly collateral lingo that permits the software coder to determine what the information handling effect ought to be and the dataflows and transformations that are required to attain the effec

The story Hadoop data value less in cost than ETL

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Traditional data warehouse That isn’t to say that Hadoop can’t be used for structured data that is readily available in a raw format; because it can.In addition, when you consider where data should be stored, you need to understand how data is stored today and what features characterize your persistence options.  Consider your experience with storing data in a traditional data warehouse. Typically, this data goes through a lot of rigor to make it into the warehouse.  Builders and consumers of warehouses have it etched in their minds that the data they are looking at in their warehouses must shine with respect to quality; subsequently, it’s cleaned up via cleansing, enrichment, matching, glossary, metadata, master data management, modeling, and other services before it’s ready for analysis.  Obviously, this can be an expensive process. Because of that expense, it’s clear that the data that lands in the warehouse is deemed not just of high value, but it has a broad purpose: it