Tech Exam Prep

ตอน

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  [PL-300] 28, CALCULATE and Context Transition 26.09.2026 3นาที

  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
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  [PL-300] 27, Building Aggregation Measures 25.09.2026 3นาที

  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
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  [PL-300] 26, DAX Syntax, Row Context, and Filter Context 24.09.2026 3นาที

  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
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  [PL-300] 25, Measures vs Calculated Columns and Tables 23.09.2026 4นาที

  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
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  [PL-300] 24, Creating a Common Date Table 22.09.2026 3นาที

  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
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  [PL-300] 23, Cross-Filter Direction and Relationship Paths 21.09.2026 4นาที

  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
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  [PL-300] 22, Relationship Cardinality 20.09.2026 3นาที

  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
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  [PL-300] 21, Role-Playing Dimensions 19.09.2026 3นาที

  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
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  [PL-300] 20, Table and Column Properties 18.09.2026 3นาที

  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
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  [PL-300] 19, Star Schema Design and Model Granularity 17.09.2026 3นาที

  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
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  [PL-300] 18, Relationship Keys and Query Load Settings 16.09.2026 3นาที

  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
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  [PL-300] 17, Merge Queries vs Append Queries 15.09.2026 4นาที

  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
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  [PL-300] 16, Reference Queries vs Duplicate Queries 14.09.2026 3นาที

  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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  [PL-300] 15, Building Fact and Dimension Tables in Power Query 13.09.2026 2นาที

  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
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  [PL-300] 14, Converting JSON, XML, and Lists into Tables 12.09.2026 4นาที

  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
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  [PL-300] 13, Pivoting, Unpivoting, and Transposing Data 11.09.2026 3นาที

  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
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  [PL-300] 12, Grouping and Aggregating Rows 10.09.2026 3นาที

  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
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  [PL-300] 11, Creating and Transforming Columns 09.09.2026 3นาที

  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
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  [PL-300] 10, Data Types, Locale, and Type Conversion 08.09.2026 3นาที

  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
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  [PL-300] 9, Fixing Nulls, Errors, and Data Quality Problems 07.09.2026 3นาที

  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