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Output to Tab - No Data from JOIN

8 - Asteroid

I have a join tool in my workflow and I am writing to 3 different tabs on an Excel document with the content of the R, L and J join results.  it is supposed to replace the tab that already exists on a file. 


I am running into issues when one of the 3 join types has no results - and as a result, the tab is not overwritten so instead of that tab being blank it is staying with whatever data was in there from before. 


Is there a way to force that tab to be "overwritten" with no results if one of the join types is blank?  can you essentially force an output with just the header values and no data? 


This is something I think that other people may need or have to figure out and Googling it didn't bring up anything useful.






9 - Comet

You know, I have not yet encountered this situation... or at least have not noticed 😛


The only simple thing I can think of is to Union a row of blank/empty fields to your Join output. If no records come out of the Join, then the Union with a "blank" record will at least give you 1 record to overwrite with. Of course, when you do have Joined records, you get an extra blank row, but the cost/penalty there may be worth the benefit in your case.




I have recreated your situation on my machine and when I ran with 'Overwrite Sheet (Drop)' option selected it will overwrite the existing file to show the header values with no data.  


If you haven't used it already I placed a block until done tool before each output data to ensure there were no error messages.   Join screenshot.png


Hope this helps.  Please can you provide more information on your workflow if you are still having difficulties.



6 - Meteoroid

Hi Nick,


Do the Block Until Done tools do anything in your workflow? I had always assumed that they would only block their own part of the workflow but do they block ALL streams of data until they are complete and then allow the other streams to run?






Hello Andy,


I thought the same thing so I thought I would test the situation.  It works if you use the block until done but doesn't work if you don't.


I have now read the documentation and it works as follows...


'Separate stream example

An Input Data tool (ID 1) and a Text Input tool (ID 2) are placed on the canvas. Each input is connected to a Block Until Done tool. The data stream with the Input Data tool runs first, regardless of which Block Until Done tool it is connected to, because its ID indicates that it was placed first.' Source 


Workflow attached.





17 - Castor
17 - Castor

Here's a post on how I'd solve this sort of problem:



17 - Castor
17 - Castor

Just seen how old this is!