Dynamic Condition Creation function

Question

I have a function which needs to create a dynamic where clause by reading the columns from the temporary table .

CREATE FUNCTION [dbo].[GetWhereClause]
(
 @TempTableName nvarchar(600)
)

RETURNS nvarchar(max) BEGIN DECLARE @sql as nvarchar(max)

 SET @sql='(SELECT STUFF('+'(SELECT space(2)+'+
 ''''+'and '+'''' +
 '+space(2)+'+''''+'B'+'.'+''''+'+'+'name+'+''''+
 ' = '+''''
 +'+'+''''+'A'+'.'+''''+'+'+'name+'+''''+''+''''+
 'from tempdb.sys.columns where object_id =
 object_id('+''''+'tempdb..'+@TempTableName+''''+')'+
 'FOR XML PATH ('+''''''+')),1, 5,'+ ''''''+'))'
RETURN @sql

END

code to see the ouput

 CREATE TABLE #SingleTempTable(ID uniqueidentifier ,Name nvarchar (50)COLLATE SQL_Latin1_General_CP1_CI_AS,Age nvarchar (50)COLLATE SQL_Latin1_General_CP1_CI_AS)
 DECLARE @QueryTable AS TABLE (ID SMALLINT IDENTITY (1, 1) PRIMARY KEY,Clause NVARCHAR (1000));
 DECLARE @sqlsource AS NVARCHAR (MAX) = '';
 DECLARE @whereClause AS NVARCHAR (MAX) = '';
 DECLARE @TempTableName AS NVARCHAR (MAX) = '#SingleTempTable'; 
 SET @sqlsource= [dbo].[GetWhereClause](@TempTableName,'') 
 INSERT INTO @QueryTable
 EXECUTE sp_executesql @sqlsource
 SELECT @whereClause=Clause FROM @QueryTable
 SELECT @whereClause

Is there any better way I can write this line in function

 SET @sql='(SELECT STUFF('+'(SELECT space(2)+'+
 ''''+'and '+'''' +
 '+space(2)+'+''''+'B'+'.'+''''+'+'+'name+'+''''+
 ' = '+''''
 +'+'+''''+'A'+'.'+''''+'+'+'name+'+''''+''+''''+
 'from tempdb.sys.columns where object_id =
 object_id('+''''+'tempdb..'+@TempTableName+''''+')'+
 'FOR XML PATH ('+''''''+')),1, 5,'+ ''''''+'))'

Now its not in a good format and its difficult to understand

Answer 1

How about this?

set @sql = '(SELECT STUFF((
 SELECT space(2)+''and ''+space(2)+''B.''+name+'' = ''+''A.''+name 
 from tempdb.sys.columns 
 where object_id = object_id(''tempdb..'+quotename(@TempTableName)+''')
 FOR XML PATH ('''')),1, 5,''''))'