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Examples of SQL queries created for Customer and Sales Data Analysis study project

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Senja-P/SQL-Customer-Sales

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SQL-Customer-Sales

Project Overview

  • The purpose of this study project was to examine the global sales revenue associated with film rentals and customers in order to help a company to launch an online film rental platform.

  • I divided countries into high, medium and low categories based on their sales and customer numbers. My advice was to focus on those countries where both sales and customer numbers were high; India, China, USA and Mexico, and select the films from the popular film genre categories based on the previous sale figures and / or the number of rentals.

  • To help management and marketing teams to work with country related strategies I provided them the country level data. I also included the top 5 cities based on the customer numbers to highlight the customer hot spots. The findings, country related data and recommendations are available on Tableau.

  • Data Limitation: The biggest limitation was the sample size; only 599 customers globally. 87% of all countries had less than 10 customers.

Analytics

  • Loaded data into a relational database management system (RDBMS), extracted a snowflake-type entity relationship diagram and explored data types, structures and keys
  • Wrote SQL queries to filter, clean, organise and summarise data
  • Used SQL to join tables, performed subqueries (inner & outer statements) and Common Table Expressions and compared performance times

Technical skills utilised

  • SQL Tool used; PostgreSQL, PgAdmin 4 (Examples of SQL queries uploaded above)
  • Excel; SQL summary data outputs from PgAdmin4 transferred into Excel, creating a Data Dictionary
  • Tableau for visualisation

Data

  • Around 3MB containing 15 files
  • Customer and sale data

Data Source

  • CareerFoundry / Study Project / Rockbuster Data Set

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