数据库字符串加法，目前没成功

declare @result nvarchar(500) declare @sql nvarchar(500) declare @tableName nvarchar(30) declare @colText nvarchar(30)  declare @colKey nvarchar(30) declare @pid nvarchar(10)   set @result=‘‘

set @tableName=‘purchase_po_in_details‘ set @colText=‘product_name‘ set @colKey=‘po_in_id‘ set @pid=6 set @result=‘‘; set @sql=‘ select @result += ‘[email protected]+‘+‘‘;‘‘ from ‘[email protected]+‘ where ‘+ @colKey+‘=‘[email protected]+‘  ‘;

exec sp_executesql @sql,N‘ @result nvarchar(500) output‘,@result output select @result