How to add static Column headers when i get "no data found" record instead of column headers.

[LeeSun]

Using below code the if statemetn is throwing error (Token Idnentifier Expected), looking for any simple solutions or solution to get rid of the error

let
Source = Excel.Workbook(Web.Contents(Mflow/NewDOM/Balancing%20Report%20from%20test.xlsx"), null, true),
#"CWP Transction Logs Report_1_Sheet" = Source{[Item="CWP Transction Logs Report_1",Kind="Sheet"]}[Data],
#"Promoted Headers" = Table.PromoteHeaders(#"Transction Logs Report_1_Sheet", [PromoteAllScalars=true]),

CheckNoData = Table.HasColumns(#"Promoted Headers",{"No Data Available"}),

= if CheckNoData = "True"
then

let
#"Promoted Headers" = #table(
type table {"LOG_ID", "TRADINGPARTNER_ID" }
)
in #"Promoted Headers"

#"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{ {"LOG_ID", Int64.Type}, {"TRADINGPARTNER_ID", type text} })

else

#"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{ {"LOG_ID", Int64.Type}, {"TRADINGPARTNER_ID", type text} })

in
#"Changed Type"

[LeeSun]

Thanks Pete, 

Given links has enabled me to complete my task.   Below solution worked for me

let
Source = Excel.Workbook(Web.Contents("Mflow/NewDOM/Balancing%20Report%20from%20Conduent.xlsx"), null, true),
#"CWP Transction Logs Report_1_Sheet" = Source{[Item="CWP Transction Logs Report_1",Kind="Sheet"]}[Data],
#"Promoted Headers" = Table.PromoteHeaders(#"CWP Transction Logs Report_1_Sheet", [PromoteAllScalars=true]),
#"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"LOG_ID", Int64.Type}, {"TRADINGPARTNER_ID", type text} }),
Custom1 = Table.SelectRows(#"Changed Type", each [ERROR_DESC] <> "Internal Outbound Service Error"),

AlternativeOutput = #table(
type table
[
#"LOG_ID"=Int64.Type,
#"TRADINGPARTNER_ID"=text
],
{}
),

TestForError= try #"Changed Type",

//If Source returns an error then return the alternative table output
//else return the value of the #"Changed Type" step
Output = if TestForError[HasError] then AlternativeOutput else Custom1
in
Output

[BA_Pete · Accepted solution]

Hi @LeeSun ,

There's a couple of standard ways to handle this sort of issue, both covered very well by Chris Webb:

To ensure all columns are always present:

https://blog.crossjoin.co.uk/2015/07/03/ensuring-columns-are-always-present-in-a-table-returned-by-p... 

To handle source errors in general:

https://blog.crossjoin.co.uk/2014/09/18/handling-data-source-errors-in-power-query/ 

IMPORTANT: Make sure to read all the comments on both blogs as there's some crucial changes/updates suggested by other readers.

Pete