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Power BI 10 Slides

Your Power BI Data is a Mess. Let's Fix It.

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Guide Notes & Explanation

Accompanying breakdown for this slide deck

  • Your Power BI Data is a Mess. Let's Fix It.

Why Clean Data?

  • Clean data builds trust in your reports
  • Accurate data leads to better business decisions
  • It prevents errors and misleading visuals
  • Saves time during analysis and troubleshooting
  • Forms a solid foundation for all your metrics
  • It is the most crucial step in any project

Remove Duplicate Rows

  • Find the option in the Home or Transform ribbon
  • Power Query identifies duplicates across all columns
  • Select specific columns to check for duplicates only there
  • Review the preview before removing to avoid mistakes
  • Removes all but the first instance of a duplicate entry
  • Essential for accurate count and sum calculations

Unpivot Your Data

  • Turns columns into rows for proper analysis
  • Fixes data spread across many column headers
  • Select the columns you want to keep as identifiers
  • Choose the columns to unpivot (often date or category columns)
  • Creates two new columns: Attribute and Value
  • Transforms wide, messy data into a tall, clean format

Split Columns Easily

  • Break one column into multiple new columns
  • Use by delimiter like a comma, space, or hyphen
  • Choose to split at each occurrence or a specific number
  • Split by number of characters for fixed-width data
  • You can split into rows instead of columns
  • Perfect for separating full names or product codes

Text Transformation Tricks

  • Use Trim to remove leading and trailing spaces
  • Clean eliminates non-printable characters
  • Change case to Upper, Lower, or Proper for consistency
  • Extract text before, after, or between delimiters
  • Replace values to fix typos or standardize categories
  • Add a conditional column for custom text rules

Date & Time Fixes

  • Change data type to Date to ensure proper recognition
  • Use the culture setting to fix day/month mix-ups
  • Extract year, quarter, month, or day name for grouping
  • Calculate age or duration using date subtraction
  • Create a date table from a simple list of dates
  • Fix invalid dates that would cause load errors

Filter & Replace Values

  • Apply filters to remove blank or null entries
  • Replace errors with a null or a default value
  • Replace specific values across the entire column
  • Use the fill feature to handle missing data
  • Filter out irrelevant rows early to improve performance
  • Preview changes immediately in the query editor

Apply & Refresh

  • All steps are recorded in the APPLIED STEPS pane
  • You can edit or delete any step at any time
  • Changes are applied only when you click Close & Apply
  • Your data model updates with the clean results
  • Set up scheduled refresh to automate the cleaning
  • Your reports now run on perfect, analysis-ready data