Forum Discussion
Union thinks column numbers are different
I am trying to make a union between two of the same table. I am following a tutorial on how to make tables incrementally load: Incrementally Load tables.
First I import the original tables the default PowerBI way which imports every column into a table. On those tables you can right click and view the source query which I copied and pasted into a new table where I simply add a where clause to the end to narrow in on the new data.
Then I go to modeling in the ribbon and create a new table with a union like so: tbl_union = UNION('tbl_old_data','tbl_new_data').
The issue is sometimes the tables will Union together just fine, then others will complain the number of columns don't match up.
The error message: "Each table argument of 'UNION' must have the same number of columns."
Each table I did this to, I followed the same exact process. It is really weird only some tables get this error and others don't. I have a feeling the problem is due to some kind of type mismatch with a column from each table. I'm pretty sure the default import is importing some columns as a different type than when the data came from a query.
Can anyone help clarify what is wrong here?
3 Replies
Hi kferrone,
If you can't ensure these columns will be changed, you can try to use SELECTCOLUMNS function to choose specific columns.
Merged Table= UNION( SELECTCOLUMNS('Table1',"COLUMN1",[Column1],"COLUMN2",[Column2],...), SELECTCOLUMNS('Table2',"COLUMN1",[Column1],"COLUMN2",[Column2],...), SELECTCOLUMNS('Table3',"COLUMN1",[Column1],"COLUMN2",[Column2],...) )You can also try use Table.InsertRows(Power query) to merge there tables.
In addition, if above not help, can you please share some sample data to test?
Regards,
Xiaoxin SHeng
Thank you. This really helped:)
