MySQL pagination stored procedure

/*
--名称：MYSQL版查询分页存储过程 
--输入参数：@fields      -- 要查询的字段用逗号隔开
--输入参数：@tables      -- 要查询的表
--输入参数：@where       -- 查询条件
--输入参数：@orderby     -- 排序字段
--输出参数：@page        -- 当前页计数从1开始
--输出参数：@pagesize    -- 每页大小
--输出参数：@totalcount  -- 总记录数
--输出参数：@pagecount   -- 总页数
--输出参数：_sumfields -- 统计字段
*/
DROP PROCEDURE IF EXISTS Proc_Page;
CREATE PROCEDURE Proc_Page
(
    in _fields varchar(2000),  
    in _tables text,
    in _where varchar(2000), 
    in _orderby varchar(200),
    in _pageindex int,
    in _pagesize int,
    in _sumfields  varchar(200),
    out _totalcount int ,
    out _pagecount int
)
begin
   set @startRow = _pageSize*(_pageIndex -1);
   set @pageSize = _pageSize; 
    set @rowindex = 0;
     set @strsql = CONCAT('select sql_calc_found_rows @rowindex:=@rowindex+1 as rownumber,',_fields,' from ',_tables,case ifnull(_where,'') when '' then '' else concat(' where ',_where) end,' order by ',_orderby,' limit ',@startRow,',',@pageSize);
     prepare strsql from @strsql;
     execute strsql;
   deallocate prepare strsql;
   set _totalcount = found_rows();
 
   if (_totalcount <= _pageSize) then
                    set _pagecount = 1;
                    else if (_totalcount % _pageSize > 0) then
                    set _pagecount = _totalcount / _pageSize + 1;
                    else
                     set _pagecount = _totalcount / _pageSize;
            end if;
        end if;
if(ifnull(_sumfields,'') <> '')
then
set @sumsql = contact('select ',_sumfields,' from ',_tables,case ifnull(_where,'') when '' then '' else concat(' where ',_where) end);
 prepare sumsql from @sumsql;
execute sumsql;
deallocate prepare sumsql;
end if;
end