Tech Exam Prep

Tech Exam Prep

Ran Chen, EA, CFP®
Land USA
Sprog EN
Episoder 127
Seneste 03.10.2026

Tech Exam Prep is a free, daily podcast covering the most in-demand IT and technology certification exams, including CompTIA Security+, AWS Cloud Practitioner, and CCNA. Each five-minute episode breaks down one exam topic with concrete examples, common exam traps, and memory tricks to help listeners pass on their first attempt. The podcast is created by Ran Chen, who holds multiple licenses and designations, and is passionate about making high-quality exam preparation accessible. For free practice questions, AI-powered explanations, and study guides, listeners can visit the OpenExamPrep website.

Episoder

  • [PL-300] 35, Formatting and Configuring Visuals 03.10.2026 3min
    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 implicit field aggregations differ from explicit DAX measures in visual configurations - Techniques for optimizing axis limits, legend visibility, and layout readability to prevent clutter - How to use small multiples for synchronized side-by-side categorical comparisons - Adding dynamic Analytics pane reference lines such as constant and average benchmarks - Configuring matrix totals and applying measure-driven conditional formatting and dynamic titles 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
  • [PL-300] 34, Choosing the Right Power BI Visual 02.10.2026 3min
    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 match core business requirements like trends, correlation, composition, and distribution to specific Power BI visuals for the PL-300 exam. - The distinction between line charts for continuous time series, bar charts for discrete categories, and scatter charts for numerical correlation. - Best practices for part-to-whole analysis, including category limits on pie charts, benefits of treemaps, and when to choose stacked bar charts. - Key exam scenarios for specialized visuals including Decomposition Trees, KPI visuals, Gauges, Matrices, and Geographic maps. - Major exam traps regarding custom visuals, misleading chart choices, and selecting built-in options to fulfill requirements efficiently. 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
  • [PL-300] 33, Optimizing Model and DAX Performance 01.10.2026 3min
    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 removing unnecessary rows and columns improves VertiPaq columnar compression in PL-300 - Techniques for reducing granularity and high cardinality, such as splitting datetime columns - Why star schemas with single-direction relationships perform best on the exam compared to bi-directional options - How to use Performance Analyzer to isolate bottlenecks between DAX query, Visual display, and Other metrics - Methods for diagnosing and rewriting slow measures using DAX Query View to eliminate costly iterators 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
  • [PL-300] 32, Semi-Additive Measures, Quick Measures, and Calculation Groups 30.09.2026 3min
    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 semi-additive measures aggregate across spatial dimensions but require last-nonblank patterns over time. - How to apply LASTNONBLANKVALUE logic to prevent incorrect summing of inventory or account balances. - The operational limits of quick measures and when explicit DAX measures are required for complex logic. - How calculation groups use the SELECTEDMEASURE function to apply dynamic logic across multiple metrics. - Criteria for choosing between reusable calculation groups and standalone explicit measures in Power BI models. 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
  • [PL-300] 31, Iterator and Statistical Functions 29.09.2026 3min
    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 differentiate standard column aggregators from row-by-row iterator functions in DAX for the PL-300 exam. - How to construct SUMX, AVERAGEX, MINX, MAXX, and COUNTX expressions using table contexts and row evaluations. - Key techniques for avoiding common RANKX traps by correctly applying ALL and ALLSELECTED functions. - How to select appropriate statistical functions including MEDIAN, percentiles, sample variance, and population standard deviation. - A quick memory rule to instantly spot when row context evaluation is required on exam 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
  • [PL-300] 30, DAX Time Intelligence 28.09.2026 3min
    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: - Essential prerequisites for proper date tables including contiguous dates and marking as a date table. - Differences between TOTALYTD and CALCULATE with DATESYTD, including custom fiscal year parameters. - When to use DATEADD versus SAMEPERIODLASTYEAR for multi-period and prior-period comparisons. - How to construct dynamic rolling window calculations using DATESINPERIOD. - The CALM mnemonic and how to avoid filter context traps with date dimension tables. 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
  • [PL-300] 29, FILTER, ALL, VALUES, and Filter Modification 27.09.2026 2min
    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 ALL and REMOVEFILTERS clear existing filter context to calculate true grand total denominators on PL-300 exam questions. - The key distinction between ALLEXCEPT and ALLSELECTED when building category and slicer-aware percentage measures. - Why VALUES includes referential integrity blank rows while DISTINCT excludes them in filter tables. - How KEEPFILTERS forces logical filter intersection rather than replacing existing filter context in CALCULATE expressions. - How to troubleshoot DAX measures incorrectly showing 100% across all visual rows due to retained filter context traps. 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
  • [PL-300] 28, CALCULATE and Context Transition 26.09.2026 3min
    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 CALCULATE modifies filter context and follows a strict evaluation order in DAX - Key differences between Boolean filters and table filters, including syntactic limitations on PL-300 - How to use KEEPFILTERS to intersect context instead of replacing existing visual filters - How context transition converts row context into filter context explicitly and implicitly through measures - Essential precautions when using CALCULATE or measure references inside calculated columns and iterators 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
  • [PL-300] 27, Building Aggregation Measures 25.09.2026 3min
    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 choose between COUNT, COUNTA, and COUNTROWS for efficient row counting in Power BI - The critical difference between DISTINCTCOUNT and DISTINCTCOUNTNOBLANK when dealing with blank values - Why the DIVIDE function must be used instead of forward slash division to safely handle divide-by-zero errors - How VAR and RETURN statements improve measure performance by evaluating expressions once in declaration context - Common exam traps on PL-300 including variable re-evaluation nuances and parameter handling in aggregation functions 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
  • [PL-300] 26, DAX Syntax, Row Context, and Filter Context 24.09.2026 3min
    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: - The crucial distinction between scalar values and table results in DAX functions for the PL-300 exam. - How row context differs from filter context and how iterators like SUMX operate line by line. - Why context transition occurs using CALCULATE and how it modifies the active filter context. - How DAX variables evaluate once upon definition and retain their frozen values across context changes. - How to avoid common exam traps involving identical-looking DAX expressions and evaluation order. 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
  • [PL-300] 25, Measures vs Calculated Columns and Tables 23.09.2026 4min
    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: - Differences in evaluation time and RAM storage between measures, calculated columns, and calculated tables. - Why calculated columns are required for slicers, visual axes, and table relationships. - How measures evaluate dynamically in filter context at query time without consuming memory storage. - Common PL-300 exam traps involving percentage aggregations and context transition in DAX. - Scenario-based decision rules for selecting calculated tables for role-playing dimensions and bridge tables. 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
  • [PL-300] 24, Creating a Common Date Table 22.09.2026 3min
    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 generate date tables using DAX functions like CALENDAR and CALENDARAUTO, including fiscal year parameters. - The strict data requirements for a valid date dimension, including continuous date ranges and zero missing dates. - How to fix text column sorting issues in Power BI visuals using the Sort By Column feature. - The process and benefits of explicitly marking a table as a date table in Power BI Desktop. - How to manage active and inactive date relationships using USERELATIONSHIP and the D.A.T.E.S. mnemonic for exam success. 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
  • [PL-300] 23, Cross-Filter Direction and Relationship Paths 21.09.2026 4min
    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: - Default to single cross-filter direction to preserve query performance and avoid circular filter logic. - Use inactive relationships with the DAX USERELATIONSHIP function to analyze role-playing dimensions like Order Date and Ship Date. - Avoid enabling bidirectional filtering across schemas as it frequently causes performance degradation and ambiguous filter paths. - Resolve model ambiguity errors by ensuring only one active relationship path exists between any two tables at a time. - Always select the least complex data modeling configuration that satisfies reporting requirements to answer PL-300 questions correctly. 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
  • [PL-300] 22, Relationship Cardinality 20.09.2026 3min
    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 select one-to-many, one-to-one, and many-to-many cardinality based on key uniqueness and table grain. - Why one-to-one relationships often indicate tables that should be merged in Power Query to reduce model complexity. - How to diagnose blank members in visuals caused by referential integrity gaps between fact and dimension tables. - Why duplicate keys in dimension tables force unwanted many-to-many relationships and how to fix them. - How to prevent ambiguous totals and double-counting caused by joining tables with mismatched grains. 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
  • [PL-300] 21, Role-Playing Dimensions 19.09.2026 3min
    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 identify role-playing dimension scenarios involving Order Date, Ship Date, and Due Date on the PL-300 exam. - The differences between duplicating date dimensions and using inactive relationships in Power BI. - When to select duplicated tables to support independent, simultaneous slicers on a report page. - How to write DAX measures using CALCULATE and USERELATIONSHIP to activate inactive date relationships. - Common exam traps regarding dataset optimization, relationship limitations, and model maintenance tradeoffs. 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
  • [PL-300] 20, Table and Column Properties 18.09.2026 3min
    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 configure Sort by Column to resolve chronological sorting issues for date and month fields in PL-300 scenarios. - The distinction between Data Type and Formatting properties, along with proper Data Category assignment for geospatial visuals. - Why setting Default Summarization to Do Not Summarize prevents incorrect aggregation of numeric identifiers like Zip Codes and Customer IDs. - Strategies for hiding technical surrogate keys and raw columns to simplify self-service reporting and improve Q&A natural language query accuracy. - Exam-tested techniques for using table and column descriptions to enhance metadata clarity for report creators. 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
  • [PL-300] 19, Star Schema Design and Model Granularity 17.09.2026 3min
    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 fact tables from dimension tables to establish optimal one-to-many relationships. - How to handle granularity mismatches across different fact tables without introducing calculation errors. - Why flattening snowflaked dimensions improves filter context propagation and VertiPaq compression. - How wide flat tables degrade Power BI model performance and break time intelligence capabilities. - How to resolve many-to-many modeling challenges without relying on risky bi-directional cross-filtering. 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
  • [PL-300] 18, Relationship Keys and Query Load Settings 16.09.2026 3min
    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 handle composite keys by concatenating columns or creating numeric surrogate keys in Power Query - Why data types must strictly match across related tables to ensure stable model relationships - How unchecking Enable Load creates connection-only staging queries without breaking downstream references - When to disable Include in Report Refresh for static historical data to reduce refresh duration - A practical mnemonic to remember key modeling and query load rules on 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
  • [PL-300] 17, Merge Queries vs Append Queries 15.09.2026 4min
    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 Merge Queries joins tables horizontally using matching key columns, while Append Queries stacks tables vertically. - The six join kinds in Power Query Merge operations, including default Left Outer and audit-oriented Left Anti joins. - How duplicate key values in a Merge table cause row count expansion and row duplication traps on the exam. - Why Append Queries requires identical column names and case sensitivity to avoid extra null-filled columns. - Clear scenario triggers to instantly choose between horizontal column enrichment and vertical row consolidation. 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
  • [PL-300] 16, Reference Queries vs Duplicate Queries 14.09.2026 3min
    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

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