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Preparing to Pass PL-300 Certification Exam: Merging vs. Appending Queries in Power BI

Written by Angelica Domenech | Dec 18, 2023

Introduction

Welcome back to the PL-300 certification exam preparation series by Pragmatic Works. In this episode, Angelica Domenech's focus is on the first functional group, "Prepare the Data," a crucial aspect of the Microsoft Power BI Data Analyst Associate certification. Before diving in, make sure to check out the first episode for an overview of the exam format and experience.


Prepare the Data Functional Group:

  • This functional group covers various skills, including getting data from sources, cleaning, transforming, and loading data.
  • Angelica recommends their 9-hour prep course on the OneMain learning platform for a detailed walkthrough of each skill.


Sample Questions - Understanding the Style:

1. Online Boutique Sales Analysis:

  • Scenario: Data analyst for a small business owner with two sheets (Week 1 Sales and Week 2 Sales) in an Excel workbook.
  • Task: Analyze sales for both weeks in a single table and query.
  • Import data from Excel into Power BI Desktop.
  • Access Power Query Editor to append Week 2 Sales into Week 1 Sales.
  • Disable loading for duplicated queries (Week 2 Sales).


2. HR Director Challenge:

  • Scenario: HR Director with two Excel files containing employee information and emergency contacts.
  • Task: Combine the two queries into one.
  • Import data from both sheets (Employee Info and Emergency Contacts) into Power BI Desktop.
  • Use Power Query Editor to merge the queries based on the matching key column (EmployeeID).
  • Disable loading for unnecessary queries (Emergency Contacts).

Power BI Desktop Walkthrough:

1. Online Boutique Sales Analysis:

  • Import data from Excel using the Excel workbook connector.
  • In Power Query Editor, append Week 2 Sales into Week 1 Sales to create a unified query.
  • Disable loading for Week 2 Sales to avoid duplication.
  • Rename and apply changes to the query.


2. HR Director Challenge:

  • Import data from both sheets (Employee Info and Emergency Contacts) using the Excel workbook connector.
  • In Power Query Editor, merge the queries based on the EmployeeID key column.
  • Disable loading for unnecessary queries (Emergency Contacts).
  • Finalize the query with required columns and settings.

 

Key Takeaways:

  • Understanding the difference between merging and appending queries is crucial.
  • Practice and familiarity with the sequence of steps are essential for success in the PL-300 exam.
  • Attention to detail, especially in disabling loading for duplicated or unnecessary queries, ensures a streamlined and accurate data preparation process.


Conclusion

In this second episode of the PL-300 certification exam preparation series, the focus has been on mastering the "Prepare the Data" functional group, specifically exploring the nuances of merging and appending queries in Power BI. The hands-on walkthrough in Power BI Desktop provides valuable insights into solving sample questions, emphasizing the importance of a structured approach. Stay tuned to the Pragmatic Works' YouTube channel for more episodes covering this certification and many other courses.

Don't forget to sign up for the Pragmatic Works' on-demand learning platform, which offers a wide range of courses, including those related to Microsoft products like Power BI, Power Automate, and Azure!