# Table Merge creates duplicate records in Power Query



## VBA learner ITG (Aug 6, 2021)

Hi Folks,

I am stumped.

I am trying to merge two tables into a new table using a LEFT JOIN.  Both tables have unique records on each row.  When I join the tables, BI creates duplicate rows on some records for no apparent reason.  The duplicates are identical in every way.

I followed the steps outlined in the below website:

Power Query Merge Table Steps

Can anybody explain this?


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## jorismoerings (Aug 6, 2021)

Hi,

This is guessing to the max without sample data but in most cases this caused because the field into the table's do have duplicate keys in them.
If you could provide a part of your file (using XL2BB) or copy of a file (no sensitive data) that shows the problem by uploading to a file-share site and provide a link here that might enable us to investigate better.


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## VBA learner ITG (Aug 6, 2021)

jorismoerings said:


> Hi,
> 
> This is guessing to the max without sample data but in most cases this caused because the field into the table's do have duplicate keys in them.
> If you could provide a part of your file (using XL2BB) or copy of a file (no sensitive data) that shows the problem by uploading to a file-share site and provide a link here that might enable us to investigate better.


Hi jorismoerings,

Thank you for taking the time to reply. You post was extremely helpful as it told me that i had duplicate keys in them which meant that the records were duplicating.

After removing the duplicates the issue has corrected itself.


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