ROWNUM查詢返回

Question

我已經習慣了rownum，並試圖理解邏輯。

舉例來說，如果一個「部門」表中包含超過10行，我們運行一個查詢，說：

Select * from Department 
where Rownum between 1 and 7 

多少行將此查詢的回報？

Answer 1

使用

select top 7 ... 
from Department 
order by some_field 

而不ROWNUM在
或使用ROW_NUMBER（）是這樣的：

with 
    dep as (select ROW_NUMBER() over (order by some_field) as lp, d.* 
    from Department d) 
select * from dep where lp between 1 and 7