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1、主要思想：根据已有数据，规则性的造数据
select * from(
select lid,strname,lid as lparentid,-1 as orderidx from tbclassify where lparentid  = 0
union all
(select t1.* from tbclassify t1 join
(select lid from tbclassify where lparentid=0 order by orderidx) t2 on
t1.lparentid = t2.lid
where 1=1 order by t1.lparentid,t1.orderidx)
) tblast where 1=1 group by tblast.lparentid,tblast.lid order by tblast.lparentid,tblast.orderidx
;
上面的排序有问题，最后成型：
select lid from(
 select lid,orderidx as pidx,-1 as sidx from tbclassify where lparentid  = 0
  union all
 (select a.lid,b.orderidx pidx,a.orderidx sidx from tbclassify a left join tbclassify b on (a.lparentid = b.lid ) where a.lparentid != 0)
)
tblast order by tblast.pidx,tblast.sidx
;
 该方法缺陷：前提必须知道树形结构共有几层，不带有通用型，当前方法只适用于两层树形结构，重点是提供了一种解决问题的思路：根据已有数据造数据
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