数据库 查询第31-40行数据，ID不连续

一、SQLServer

大致分为两种情况：ID连续和ID不连续。

1.ID连续的情况：

select * from A where ID between 31 and 40

2.ID不连续的情况：

(1).两次对表查询，效率较低。

select top 10 * from A where ID not in (select top 30 ID from A)
(2).外层查询没有对表A进行查询，效率提高。

select top 10 * from (select top 40 ID from A order by ID) as a order by a.ID desc 

(3).ROW_NUMBER()函数效率更高,SQL2005以上版本可用。

select * from(select *,ROW_NUMBER() over(order by ID)as 'userID' from A) as a where a.userID between 31 and 40

二、Oracle

select * from (select row_num as rid,* from A where rid <=40 ) t1 where t1.rid>=31;(必须两层嵌套)

嵌套原因参考：https://www.cnblogs.com/songhengchao/p/8996255.html

分页查询语句：

1：单表查询

SELECT * FROM (SELECT t.*,ROWNUM r FROM TABLE t WHERE ROWNUM <= pageNumber*pageSize) WHERE r >(pageNumber)*pageSize

2：两张表联查

SELECT * FROM (SELECT ROWNUM RN,XX.* FROM (SELECT 表名.字段名, 表名.字段名, 表名.字段名... FROM TABLE1  t1, TABLE2   t2 WHERE t1.字段=t2.字段) XX WHERE ROWNUM<=pageSize*pageNumber) WHERE RN >(pageNumber-1)*pageSize