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EllianHs
Frequent Visitor

PowerBi Append two table with error message "Expression.Error: The field 'xxx' already exists

Hi 

 

I started getting errors this week (3/13/2023) when processing append tables in power query.

The message descrinbes there is a certain field has exist but from my understadning, when appending two tables, there shouldn't

has such limitatioion. Anyone could share some light what might go wrong? Capture.PNG

Ellian

1 ACCEPTED SOLUTION
artemus
Microsoft Employee
Microsoft Employee

Does adding Table.StopFolding(<<table>>) around both tables still result in an error?

I.e.

Table.Combine({Table.StopFolding(<<table>>), Table.StopFolding(<<table>>)})

 

Also, what version of Power Bi (or Excel) are you using?

View solution in original post

9 REPLIES 9
wdx223_Daniel
Super User
Super User

it seems the error comes from those two tables

artemus
Microsoft Employee
Microsoft Employee

What is your data source type?

While this is probably a bug with the way the data source does combine, it is probably caused by a different casing between the two columns.

The data source is data flow. It actually was acting fine but one day the dataset for the report refresh failed and has the error. If I removed the columns throw out the erros, it will just show the next column giving the errors

artemus
Microsoft Employee
Microsoft Employee

Does adding Table.StopFolding(<<table>>) around both tables still result in an error?

I.e.

Table.Combine({Table.StopFolding(<<table>>), Table.StopFolding(<<table>>)})

 

Also, what version of Power Bi (or Excel) are you using?

Hi @artemus,

 

I've stumbled across this while trying to solve this very issue.

I was doing a very simple Table.Combine() with two Dataflows and it was throwing an error that made no sense.

 

Can you explain this solution and what has changed to cause this to be needed?

Do I need to go and check other Datasets that have this Table.Combine() logic?

 

Thanks.

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artemus
Microsoft Employee
Microsoft Employee

If this works it indicates there is a bug in the datasource folding implementation (or less likely the power query engine). This funcation forcable breaks folding and as a result works around the bug.

It did work.

The Datasource is Dataflows using the PowerPlatform.Dataflows() connector in my case.

I wasted 3 hours thinking I was doing something wrong, so was glad to find this post. 

Would love to know what has changed and whether this will potentially break existing Datasets.

 

Have I solved your problem?
Please click Accept as Solution so I don't keep coming back to this post, oh yeah, others may find it useful also ;).
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If you found this post helpful, please give Kudos.
It gives me a sense of instant gratification and, if you give me Kudos enough times, magical unicorns will appear on your screen.
If you find my signature vaguely amusing, please give Kudos.
KIfp67uy-Sr
Proud to be a Super User!PBI-Super-User-Rank-30x30-1x
artemus
Microsoft Employee
Microsoft Employee

I would also like to know, but haven't been able to reporduce this problem.

Yes, it works !! :). I have Version: 2.114.864.0 64-bit (February 2023).

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