不知道为什么，这么写就对了的------MSSQL引号和时间日期

  declare @mouth int
  --declare @start datetime
  --declare @end datetime
  declare @start nvarchar(20)
  declare @end nvarchar(20)
  declare @str nvarchar(3000)
  declare @sql nvarchar(3000)

  set @mouth=1
  while @mouth<=12
  begin
  
   if @mouth=12
   begin
  set @start='2011-'+STR(@mouth)+'-1'
  --set @start=cast(@str as datetime)
  set @end='2012-'+STR(@mouth)+'-1'
  --set @end=cast(@str as datetime)
   end
   else
   begin
  set @start='2011-'+ltrim(rtrim(STR(@mouth)))+'-1'
  --set @start=cast(@str as datetime)
  set @end='2011-'+ltrim(rtrim(STR(@mouth+1)))+'-1'
  --set @end=cast(@str as datetime)
   end
  
   set @sql=N'select '+ltrim(rtrim(cast(@mouth as CHAR)))+' as ''月份'',count(1) as ''单数'',SUM(amount) as ''金额'' FROM [szjdw].[dbo].[mf_order] where cop_id=''DGJDW'' and createdt>'''+@start+''' and createdt<'''+@end+''''
      select @sql
      --exec(@sql)
   set @mouth=@mouth+1
  end
  go