-- (m+1)为取出行的起始序号
-- n 为取出的全部行数
select * from table where...
limit m,n
 
-- 上述语句等价于
select * from table shere...
limit pageSize offset firstIndex

-- 显示student表31~50行，共20行的结果
select * from student limit 30,50
 
-- 或者
select * from student limit 50 offset 30

-- 表示从第一条记录行开始取出m条数据
select * from table where...
limit m

-- 表示 85分以上的前十名学生
select * from student where score>85 order by score DESC
limit 10

select * from
　　(select a.*,ROWNUM rn from(sql) a 
　　where ROWNUM<=(firstIndex+pageSize)) -- 内层控制最大值
where rn>firstIndex -- 外层控制最小值

SELECT * FROM  
　　(  
　　SELECT A.*, ROWNUM RN  
　　FROM (SELECT * FROM TABLE_NAME) A  
　　WHERE ROWNUM <= 40  -- 末序号，20*2 
　　)  
WHERE RN >= 21 -- 起始序号

select * from
　　(select a.*,row_number() over(order by a.score DESC) orderNum 
　　from student a)
where orderNum between 21 and 40

-- 首先查出该字段重复的数据
select * from [TABLE] group by [ID] having count[ID] > 1
-- 字段重复的数据中，找出rowid较小的那些数据
select min(rowid) from [TABLE] group by [ID] having count(*) > 1
-- 删除多余的数据，只保留重复数据中rowid较小的那个
delete * from [TABLE]
where [id] in ( select * from [TABLE] group by [ID] having count[ID] > 1 )
and
rowid not in ( select min(rowid) from [TABLE] group by [ID] having count(*) > 1 )

-- 首先查出多字段重复的数据
select * from 表 a
where (a.[ID],a.[field]) IN
(
select [ID], [filed] from [TABLE]  
group by [ID],[field] having count(*) > 1
)
-- 删除多余的数据，且rowid为小的
delete from 表 a 
where (a.ID,a.[field]) in 
(select ID,[field] from 表 group by ID,[field] having count(*) > 1) 
and 
rowid not in (select min(rowid) from 表 group by ID,[field] having count(*)>1)

select top num from table_name
where...

select top 10 from student order by score