Question

Handling Text-Based Date Columns with Errors in Power Query
Your dataset has a "Date" column stored as text (e.g., "2024-02-15"), and converting it to a Date format causes errors for some values. What steps should you take in Power Query to correctly transform this column while handling any inconsistencies or errors?

Answer 1

To correctly transform a text-based date column in Power Query while handling errors, follow these steps:

1. Identify and Inspect the Errors

• Open Power Query Editor.
• Check the "Date" column for inconsistencies:
  • Mismatched formats (e.g., "2024/02/15", "15-02-2024").
  • Blank, null, or non-date values (e.g., "N/A").

2. Trim and Clean the Data

• Add a Custom Column to remove unwanted spaces and characters

= Text.Trim([Date])

Replace empty values with null to prevent errors:

= if [Date] = "" then null else [Date]

3. Safe Conversion To Date Format

• Option 1: Direct Conversion (If Format Is Consistent)

Select the column → Click Transform → Change Type → Date.

Any resulting errors? If so, proceed to option 2.

• Option 2: Deal with More Possible Date Formats

Use a Custom Column to try not to break the query:

= try Date.FromText([Date]) otherwise null

• This converts valid dates and replaces errors with null.

If the dates are in mixed formats, use Date.From with a locale setting:

= try Date.FromText([Date], "en-US") otherwise try Date.FromText([Date], "fr-FR") otherwise null

Adjust locale as needed (e.g., "en-GB" for DD/MM/YYYY).

4. Replace or Flag Errors for Review

• Use "Replace Errors" in Power Query to set errors to null or a default date (e.g., "1900-01-01").
• Alternatively, create an Error Flag Column for review

= if try Date.FromText([Date]) is null then "Error" else "Valid"