Stored procedure to export result to excel header not displayed

Question

Hi,
I am using below stored procedure to export data to excel with header. but it is not displaying the header . i believe this is because the max length of query can be 8000. but  I have more than 250 columns so probably the length of query is breaking
the code.
can someone please help here.
Thanks in advance.
ALTER procedure [dbo].[proc_generate_excel_with_columns]
@table_name varchar(100),
@file_name varchar(100)
as
--Generate column names as a recordset
declare @columns varchar(8000), @sql varchar(8000), @data_file varchar(100)
select
@columns=coalesce(@columns+',','')+column_name+' as '+column_name
from
information_schema.columns
where
table_name=@table_name
select @columns=''''+replace(replace(@columns,' as ',''' as '),',',',''')
--Create a dummy file to have actual data
select @data_file=substring(@file_name,1,len(@file_name)-charindex('\',reverse(@file_name)))+'\data_file.csv'
--Generate column names in the passed EXCEL file
set @sql='bcp "select * from (select ' + @columns + ') as header" queryout E:\test.csv -c -t, -T -S ' + @@servername
exec master..xp_cmdshell @sql
--Generate data in the dummy file
set @sql='bcp "select * from CustomerTable where ReservationDate>''1/1/2013''" queryout E:\data_file.csv -c -t, -T -S' + @@servername
exec master..xp_cmdshell @sql
--Copy dummy file to passed EXCEL file
set @sql= 'exec master..xp_cmdshell ''type '+@data_file+' >> "'+@file_name+'"'''
exec(@sql)
----Delete dummy file
set @sql= 'exec master..xp_cmdshell ''del '+@data_file+''''
exec(@sql)
--EXEC proc_generate_excel_with_columns 'CustomerTable','E:\test.csv'

Answer 1

Can you try to print the @columns?
In the same procedure can you change size of @columns to varchar(max) and try executing the procedure?
ALTER procedure [dbo].[proc_generate_excel_with_columns]
@table_name varchar(100),
@file_name varchar(100)
as
--Generate column names as a recordset
declare @columns varchar(max), @sql varchar(max), @data_file varchar(100)
select
@columns=coalesce(@columns+',','')+column_name+' as '+column_name
from
information_schema.columns
where
table_name=@table_name
select @columns=''''+replace(replace(@columns,' as ',''' as '),',',',''')
print @Columns
--Create a dummy file to have actual data
select @data_file=substring(@file_name,1,len(@file_name)-charindex('\',reverse(@file_name)))+'\data_file.csv'
--Generate column names in the passed EXCEL file
set @sql='bcp "select * from (select ' + @columns + ') as header" queryout E:\test.csv -c -t, -T -S ' + @@servername
exec master..xp_cmdshell @sql
--Generate data in the dummy file
set @sql='bcp "select * from CustomerTable where ReservationDate>''1/1/2013''" queryout E:\data_file.csv -c -t, -T -S' + @@servername
exec master..xp_cmdshell @sql
--Copy dummy file to passed EXCEL file
set @sql= 'exec master..xp_cmdshell ''type '+@data_file+' >> "'+@file_name+'"'''
exec(@sql)
----Delete dummy file
set @sql= 'exec master..xp_cmdshell ''del '+@data_file+''''
exec(@sql)
--EXEC proc_generate_excel_with_columns 'CustomerTable','E:\test.csv'
--Prashanth