高效的多表分页查询代码

select *
FROM(SELECT id, frmNum, cost_price, wholesale_price, pic, lpic1, shopid,  stylename,caizhiname, Row_Number() OVER (ORDER BY id DESC) AS rownum
FROM (SELECT Frm.id, Frm.frmNum, Frm.cost_price, Frm.wholesale_price,  Frm.pic,
              Frm.lpic1, Frm.sid AS shopid, FrmStyles.name AS  stylename,
              CaiZhiClass.name AS caizhiname
        FROM Frm LEFT OUTER JOIN
              FrmStyles ON FrmStyles.id = Frm.frmstyles LEFT OUTER  JOIN
              CaiZhiClass ON CaiZhiClass.id = Frm.frmcz) AS t
WHERE (shopid = 'shop100206')) AS b
WHERE b.rownum>1 AND b.rownum<20