Tech Exam Prep

Tech Exam Prep

By Ran Chen, EA, CFP®EducationHow ToCourses
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Tech Exam Prep episodes

  • [PL-300] 16, Reference Queries vs Duplicate Queries
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How reference queries maintain parent-child lineage and automatically inherit upstream transformations in Power Query.
    - Why duplicate queries create independent M code scripts without ongoing dependencies or automatic updates from the original query.
    - Best practices for staging queries, including disabling load and referencing staging tables to build star schema fact and dimension tables.
    - Common PL-300 exam traps involving breaking changes in upstream queries and maintenance overhead in duplicated pipelines.
    - The mental shortcut Reference Remembers, Duplicate Disconnects to quickly solve query architectural scenarios on exam day.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 15, Building Fact and Dimension Tables in Power Query
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to transform flat source data into fact and dimension tables in Power Query for the PL-300 exam
    - Why applying Remove Duplicates on dimension key columns is critical to prevent many-to-many relationships
    - How to establish and match correct granularity between fact and dimension tables
    - Key differences between referencing and duplicating queries when building data models
    - Common PL-300 exam traps involving query transformations and star schema design
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    3 min
  • [PL-300] 14, Converting JSON, XML, and Lists into Tables
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to convert top-level JSON and XML list structures into tables using Power Query
    - The functional difference between expanding Record columns horizontally versus List columns vertically
    - Techniques for using Extract Values with delimiters to prevent accidental row multiplication
    - How to identify and avoid cartesian product traps when expanding multiple nested lists
    - Step-by-step methods to navigate nested XML attributes and REST API JSON payloads for PL-300 scenarios
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    5 min
  • [PL-300] 13, Pivoting, Unpivoting, and Transposing Data
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - Why Unpivot Other Columns is necessary to dynamically absorb newly added period columns
    - The critical distinction between structural grid rotation using Transpose and data normalization using Unpivot
    - How to properly configure Pivot Column advanced options to handle text values without unwanted aggregation
    - How to transform matrix-shaped raw spreadsheet data into an analytics-ready tabular structure
    - Common PL-300 exam traps involving hardcoded column references versus resilient Power Query M code steps
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 12, Grouping and Aggregating Rows
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How single and multiple key combinations dictate table granularity during Group By operations in Power Query.
    - The role of standard aggregations like Count, Sum, Average, Min, Max, and Count Distinct in data reduction.
    - How the All Rows operation creates nested tables to retain detail while performing group-level calculations.
    - Exam strategies for avoiding detail loss traps through merging aggregated tables or expanding nested tables.
    - M code syntax patterns for Table.Group and performance trade-offs of early data aggregation for the PL-300 exam.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 11, Creating and Transforming Columns
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to distinguish between Power Query transformations and DAX calculated columns for optimal Power BI performance
    - How to utilize conditional, custom, index, duplicate, split, and merge column features in Power Query
    - How to apply extract, replace, and format text operations accurately during data preparation
    - Key exam traps regarding transforming existing columns versus adding new columns in Power Query
    - A memorable mental shortcut to instantly identify the right architecture on PL-300 scenario questions
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 10, Data Types, Locale, and Type Conversion
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - Key distinction between decimal and fixed decimal for financial accuracy in Power BI
    - How duration differs from time and why incorrect types break aggregations and dataset refresh
    - How to handle international dates and numbers using Change Type using Locale in Power Query
    - Why mismatched data types break table relationships, sorting, and DAX calculations
    - Exam strategies for choosing early Power Query ETL type conversion over Desktop Data view
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 9, Fixing Nulls, Errors, and Data Quality Problems
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How replacing errors with zero versus leaving nulls impacts DAX measures like AVERAGE and DIVIDE
    - The critical functional difference between Remove Errors and Keep Errors when diagnosing data anomalies
    - Best practices for using Fill Down and Fill Up to handle parent-child hierarchy gaps
    - How step order and text trimming affect deduplication and inconsistent label cleanup in Power Query
    - Strategies for resolving folder import failures and schema changes using robust Power Query error handling
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 8, Data Profiling, Column Quality, and Statistics
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How Column Quality, Distribution, and Profile features function in Power Query Editor for PL-300.
    - The critical difference between Distinct values (total unique types) and Unique values (values appearing exactly once).
    - How to interpret summary statistics like minimum, maximum, top, and bottom values in Column Profile.
    - How to troubleshoot missing errors by switching profiling scope from top 1,000 rows to the entire dataset.
    - The performance trade-offs associated with profiling entire large datasets versus sampling top rows.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    5 min
  • [PL-300] 7, Creating and Using Power Query Parameters
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How Power Query parameters dynamically modify server names, file paths, dates, and environment settings at the M code data ingestion layer
    - How to configure data types, default values, and parameter lists in Power Query Editor for reusable filtering
    - The critical architectural differences between Power Query parameters, What-If numeric range parameters, and field parameters
    - Key PL-300 exam indicators for choosing the correct parameter type based on business scenarios
    - A memorable shortcut phrase to quickly distinguish source transformations from report-level DAX interactions
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min

About Tech Exam Prep

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Tech Exam Prep is a free, daily podcast by OpenExamPrep covering the most in-demand IT and technology certification exams — including CompTIA Security+, AWS Cloud Practitioner, CompTIA Network+, CCNA,…