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yui_'s avatar
yui_
Regular Visitor
1 month ago

Power BI Import changes text case when only letter casing differs

I am using Power BI Desktop (November 2025) with Import mode from an Oracle View.

I have encountered an issue where text values that differ only by the case of alphabetic characters are displayed with the same casing after being loaded into the Power BI data model.

Example

In Oracle, the data is stored correctly:

Item CodeItem Name

A001Bottle 100ML
C001Bottle 100mL

However, in Power BI, both rows are displayed as:

Item CodeItem Name
A001Bottle 100ML
C001Bottle 100ML

The same issue occurs with values such as:

  • 1LR → 1Lr
  • 600R → 600r

In every case, only the letter casing differs.

Environment

  • Power BI Desktop (November 2025)
  • Import mode
  • Oracle View as the data source

Investigation performed

Oracle

The data is stored correctly.

Power Query

In the Power Query Editor ("Transform Data"), the values are still displayed correctly, including the different letter casing.

Data Model

After clicking Close & Apply, the Table View (Data Model) already shows the values with the same casing.

Therefore, the issue appears before any report visual is involved.

Additional checks

  • The column is not sorted by another column ("Sort by Column" is set to itself).
  • The same behavior occurs in both Table visual and Matrix visual.
  • Using Binary.ToText(Text.ToBinary([Item Name]), BinaryEncoding.Hex) confirms that the underlying byte sequences are different in Power Query.
  • If I append a visible character (such as #) in Power Query, Power BI correctly distinguishes the values.
  • Appending a Zero Width Space (U+200B) does not solve the problem.

Questions

  1. Is this a known limitation or bug in the VertiPaq engine or Power BI Import mode?
  2. Has anyone experienced the same issue?
  3. Is there any way to preserve the original letter casing without changing the visible text?

Any suggestions or workarounds would be greatly appreciated.

Thank you very much for your help.

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4 Replies

  • johnt75's avatar
    johnt75
    Icon for Super User rankSuper User
    1 month ago

    This is expected behaviour. While Power Query is case sensitive, DAX is not. The exact case which is stored depends on the order the data is loaded, e.g. if "100ML" is loaded before "100ml" then all values will be stored as "100ML". If no explicit order is specified in the query then the ordering could potentially change each time the data is loaded, depending on the behaviour of the underlying DB engine.

    • yui_'s avatar
      yui_
      Regular Visitor
      1 month ago

      Thank you very much for your explanation.

      So, if I understand correctly, this means there is currently no way to preserve the original letter casing (for example, "100mL" and "100ML") when using Import mode in Power BI, and this behavior is expected.

      Although this is not the answer I was hoping for, I appreciate your clear explanation. Thank you for taking the time to help me.

      • johnt75's avatar
        johnt75
        Icon for Super User rankSuper User
        1 month ago

        You understand correctly, there is no way to do it.