# Expression.Error: We cannot convert the value null to type Text. Details: Value= Type=Type



## Stacker (Jul 11, 2021)

This video basically has what I want to do with regards to using power queries to join multiple files to a file despite them having different headings.  Whilst following the video I got to about 12 mins in and it failed saying "Expression.Error: We cannot convert the value null to type Text. Details: Value= Type=Type". The code I used before it failed was this:

= Table.TransformColumnNames(Topp_Table, each List.Accumulate(Table.ToRecords(Headings), _ , (state, current)=>Text.Replace(Text.Upper(state), current [BEFORE],current[AFTER]) )). 
 What can I do to fix this? I had one blank table with just headings,whilst the other two tables had their own things. Sorry for the two posts. I don't know how to edit and accidentally hit send


----------

