Introduction to Oracle Profiling functions: Sorting

There are 3 kinds of analytic functions commonly used by Oracle for sorting, rank (), Dense_rank (), row_number ();

The test table is as follows:

1, rank () Jump ranking

With temp as

(

Select T_id,t_age, rank (t_age desc) sec from AAA

)

SELECT * FROM Temp

--where sec=1--, Plus this filter, you can find records that are ranked 1

If you specify a group, the following are:

With temp as

(

Select T_id,t_age, Rank () over (partition by t_id-by-t_age desc) sec from AAA

)

SELECT * FROM Temp

--where sec=1--is ranked 1 in each group.

2, Dense_rank () normal (non-jump) ranking

With temp as

(

Select T_id,t_age, Dense_rank () over (order by t_age desc) sec from AAA

)

SELECT * FROM Temp

--where sec=1

This column more highlights: http://www.bianceng.cnhttp://www.bianceng.cn/database/Oracle/