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zaherbilal
Frequent Visitor
1 year ago
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Dataflow Gen2 to Warehouse - Date Column Type Mismatch Error

Hello Fabric Community,

I'm encountering a persistent error when trying to write a simple date column from Dataflow Gen2 to a new Warehouse table. Despite multiple attempts to enforce the correct data type, I keep getting a type mismatch error.

 

Error Details:

Query _WriteToDataDestination: There was a problem refreshing the dataflow:
'Couldn't refresh the entity because of an issue with the mashup document MashupException.Error:
We can't update the table. The type of column 'Import_Date' doesn't match the type of the column in the table.
Details: Reason = Expression.Error; ErrorCode = 10557;
 

Reproductions Steps:

  1. Dataflow Gen2 Query:

let
Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjIwMtI3MNU3MFGKjQUA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t]),
#"Changed column type" = Table.TransformColumnTypes(Source, {{"Column1", type date}})
in
#"Changed column type"
 

  1. Destination Settings:

    • Warehouse: New table

    • Update Method: Replace

    • Schema: Fixed

    • Column Mapping: Column1 (Date → Date)

What I've Tried:

  1. Simplified the query to use #date() hardcoded values
  2. Explicitly converted dates to text (yyyy-MM-dd) and back to type date
  3. Used locale-invariant parsing ("en-US")
  4. Verified schema with Table.Schema() (shows type date)

 

Questions:

  1. Is there a known issue with Dataflow Gen2 writing type date to Warehouse tables?

  2. Are there additional settings required in the Warehouse destination?

  3. Could this be related to regional settings or service updates?

Any guidance or workarounds would be greatly appreciated!

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