Data Explorer seems to half attempt to nest comments

Question

I have embedded a start comment in a comment in this query and its Order By clause is ignored:

Select 1 As [F]
Union all
Select 2 As [F]
/*/**/
Order By [F] DESC

...yields:

 F
--
 1
 2

Answer 1

The real issue is that you don't get a syntax exception for not closing the second comment. Running the SQL as-is produces the following error in SSMS:

Msg 113, Level 15, State 1, Line 5
Missing end comment mark '*/'.

Data Explorer is currently removing comments from your query prior to execution, and doesn't handle cases like this appropriately. I'll see what can be done about cases like this; it might just be better if Data Explorer doesn't try to do what it's doing now so errors like this would be thrown by SQL Server.

For right now though, I took care of this specific case.