Expression.Error: We cannot convert the value null to type Number

[DanielHart]

Hi All,

I am receiving the following error when trying to merge two tables:

Expression.Error: We cannot convert the value null to type Number.
Details:
Value=
Type=[Type]

There are no null values in either table (checked that thoroughly), and no conversion to Numbers. I have created a custom column in each table with exact data to merge on. The scenario for the merge is I have a table with datetime values and I am trying to merge a second table with datetime values. Doing a Left Outer join to only return the rows from the first table, and the matching rows from the second table.

This error is doing my head in, and can not figure out what is causing it. Can not find any other resources on the web with the same error when merging.

Any assistance would be greatly appreciated.

[DanielHart · Accepted solution]

Hi vanessafvg,

I have found the problem. Long story short, there was some bad data in a single json file I was parsing (out of a database of 20,000+ json files). Took a while to find it, but after filtering out that file, the problem is resolved. 

Thanks for looking at my question though. 

[v-eqin-msft]

Hi @DanielHart ,

Could you please kindly Accept your reply as the solution to make the thread closed since your issue has been resolved ? More people will benefit from it. 

Thanks in advanced!😀

Best Regards,
Eyelyn Qin

[vanessafvg]

are you able to share the data?   when you say you have checked thoroughly, how have you checked?  can you do a unique list from each column and share those values?