How can I stop a query from proceeding to the next steps if the table is blank?

[dehmos27]

I have a scenario where I want to prevent a query from erroring out if a table is blank by stopping it from evaluation additional steps. Is there a way to do this?

Here's the background: a dataset is extracted from a system as one file type, but the query only works with files of a specific type, so I want to stop the query from running if the referenced file is NOT of the correct file type but leave the report blank instead of erroring out.

[mahoneypat · Accepted solution]

Multiple ways you can do this.  If the file is one of many, but has an error, you can add a step to remove errors (right click on that column to see that option) before proceeding.  If it is the only file, you can build a "try ... otherwise" in your query somewhere at the step level 

step= try prevstep otherwise null (or some acceptable output)

Not sure what you'll need to do with your otherwise w/o seeing the rest of your query, but you can use it to substitute in dummy data that works, null, etc. 

If this works for you, please mark it as solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat

[edhans · Accepted solution]

Try this. 

Do the query as normal. Then for the last step add something like this. Add a new step to your query by right-clicking on the last step and adding another step. type this in the formula bar:

= if Table.IsEmpty(#”Step Where it could be empty”) then null else #”Previous Step”

(My iPhone is putting weird quotes here so fix those if you copy paste)

You may need to replace null with something else if null will cause problems later on or have other error handling in subsequent queries to handle the null. 

I’d really have to see what the query is doing and how it is being relied upon later to be more specific. 

[mahoneypat · Accepted solution]

Multiple ways you can do this.  If the file is one of many, but has an error, you can add a step to remove errors (right click on that column to see that option) before proceeding.  If it is the only file, you can build a "try ... otherwise" in your query somewhere at the step level 

step= try prevstep otherwise null (or some acceptable output)

Not sure what you'll need to do with your otherwise w/o seeing the rest of your query, but you can use it to substitute in dummy data that works, null, etc. 

If this works for you, please mark it as solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat