Help on handling errors?

[jjku]

I cannot figure out how to insert the IF xxx[HasError]  else  xxx then  into this statement.

= Table.AddColumn(#"Added Custom9", "Entity", each ( let currentEntryNoKey = [Entry_No_Key] in Table.SelectRows(All_Vendor_Ledger, each [Entry_No_Key] = currentEntryNoKey)) 
{0}[Vendor_Name])

Basically, if there is an error, I just want it to return blank. If there is no error, then return the {0}[Vendor_Name]

[watkinnc · Accepted solution]

OK, if you just want a value from that table, or null each time there is an error, I would do it like this, so there are no scope issues.  Add a new step, name it EntryKeyList, then in the formula bar, type:

= List.Buffer(#"Added Custom9"[Entry_No_Key])

Add a new step, name it NewThing (or whatever), then in the formula bar:

= Table.AddColumn(EntryKey, "Entity" each try Table.SelectRows(All_Vendor_Ledger, each List.Contains([Entry_No_Key], EntryKeyList)){0}[Vendor_Name] otherwise null)

--Nate

Entity = Table.AddColumn(

[jjku]

I will try this fix and report back. Thanks!

[jjku]

Yes. I guess my problem is where do I put the Try and the Else.. I can't seem to figure that out.

I did try this:

= Table.AddColumn(#"Added Custom9", "Entity", each ( let currentEntryNoKey = [Entry_No_Key] in Table.SelectRows(All_Vendor_Ledger, each [Entry_No_Key] = currentEntryNoKey)), 
try {0}[Vendor_Name] otherwise "null")

but now I get a We cannot convert the value "null" to type Type.

[jjku]

I changed it to this...

= Table.AddColumn(#"Added Custom9", "Entity", each ( let currentEntryNoKey = [Entry_No_Key] in Table.SelectRows(All_Vendor_Ledger, each [Entry_No_Key] = currentEntryNoKey)),
try {0}[Vendor_Name] otherwise Null.Type)

it seems to work, but my new problem is that the null results says TABLE, and not null.

[watkinnc]

Not Null.Type, just null. 

[jjku]

When i put null.. the result for all the null say  table. But nothing is in that table. 

I can't get my head around the TYPE. 

[AlexisOlson]

The standard method in M is with "try" ... "otherwise". In your case, "try xxx otherwise null" with return xxx if there isn't an error and a null otherwise.

https://docs.microsoft.com/en-us/power-query/handlingerrors