mysql 分页存储过程

CREATE PROCEDURE sp_GetInfo(
in _where varchar(2000),
in _orderby varcahr(200),
in _pageindex int,
in _pagesize int,
out _totalcount)
BEGIN
  SET @startrow = _pagesize * (_pageindex - 1) ;
  SET @pagesize = _pagesize ;
    set @strsql=‘select * from feedback‘;
  SET @strwhere = CONCAT(
    CASE
      IFNULL(_where, ‘‘) 
      WHEN ‘‘
      THEN ‘‘
      ELSE CONCAT(‘ where 1=1 ‘, _where) 
    END,
      CASE
      IFNULL(_orderby, ‘‘) 
      WHEN ‘‘
      THEN ‘‘
      ELSE CONCAT(‘ order by ‘, _orderby) 
    END
  ) ;
    set @sql1=CONCAT(@strsql,@strwhere);
    PREPARE sql1 FROM @sql1;
    EXECUTE sql1;
    SET _totalcount = FOUND_ROWS();
    
    set @sql2=CONCAT(@strsql,@strwhere,
            CASE
                WHEN _pagesize=0
                THEN ‘‘
            ELSE CONCAT(‘ limit ‘,@startRow,‘,‘,@pageSize)
            END);
  PREPARE sql2 FROM @sql2;
  EXECUTE sql2 ;
    
END