What is SQL Server TEXT_LEX

Question

I was writing a T-SQL query with FOR XML RAW(...). I have always use a string literal for the argument for "RAW()". I wanted to see if it would take a variable. When I put in a variable, I got a red squiggly underline (as I pretty much expected). When I hovered it, the pop-up message was "Incorrect syntax near '@VarName'. Expecting STRING, or TEXT_LEX." What is a TEXT_LEX? How do I create a TEXT_LEX?

I know there are many places in T-SQL where a string literal is required and a variable will not work. I am NOT asking why I got the message. I am asking what TEXT_LEX in the message is.

Answer 1

Local variables cannot be used in RAW, but it is possible to use scripting variables:

SELECT … FOR XML RAW($(x))

These variables are specified in command line of SQLCMD utility:

SQLCMD -v x="'abc'" …,

which results in RAW('abc').

IntelliSense accepts such constructs if you enable the “SQLCMD Mode” in Query menu.

Maybe TEXT_LEX means such kind of indirect text lexemes.

Answer 2

That's an implementation detail of the TSQL parser used in SSMS for syntax highlighting. The source code is not on GitHub, so I don't know what the parser is looking for exactly there.

But per the docs, there's nothing other than a literal string that can appear inside the RAW(). https://learn.microsoft.com/en-us/sql/t-sql/queries/select-for-clause-transact-sql?view=sql-server-ver15

You can see how that parser tokenizes the batch like this:

        static void Main(string[] args)  
        {  
  
            var sql = @"  
declare @f varchar(20)  
  
SELECT SalesOrderID  
FROM Sales.SalesOrderDetail  
WHERE SalesOrderID = 43892  
  AND ProductID = 758  
for xml raw(@f)  
";  
                          
            var result = Microsoft.SqlServer.Management.SqlParser.Parser.Parser.Parse(sql);  
            foreach (var e in result.Errors)  
            {  
                Console.WriteLine(e.Message);  
            }  
            foreach (var t in result.Script.Batches.First().Tokens)  
            {  
                Console.WriteLine($"Token {t.Type}: \"{t.Text}\"");  
            }  
        }  

Answer 3

Hi @JediSQL ,

Thank you so much for posting here.

I took a lot of efforts to do some research about TEXT_LEX but failed to find any offcial document about its declaration and creation method.

Per my understanding,TEXT_LEX is something like TEXT or STRING and you could focus on the solution to this error.

You could post your complete code if possbile and we could check further.

Best regards
Melissa

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Answer 4

Thank you, everyone. Thank you anonymous usere-msft and @MelissaMa-MSFT for the time spent on research. Thank you @Viorel for staying away from "why the error" and introducing me to the word lexeme.