> 有张千万级别的日志表，分页拉取数据批处理。
## 总结使用
```sql
select * from (
select rownum rn,t1.* FROM (
查询语句
) t1 where rownum<=pageSize*pageNum
) t2 where t2.rn>(pageSize-1)*pageNum
```
- 下面分页语句查询耗时4.430s。
```sql
SELECT * from(
select rownum rn,e.* from (select * from IMF_REQ_LOG) e
)
where rn>20000 and rn<=20020
```
- 优化后语句,查询耗时0.330s。
```sql
select * from (
select rownum rn,t1.* FROM (
select * from IMF_REQ_LOG
) t1 where rownum<=20020
) t2 where t2.rn>20000
```
Oracle分页语句优化
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