在視窗上使用彙總函式

SQL Server 的時間序列分析

Maham Faisal Khan

Senior Data Science Content Developer

排名函式

`ROW_NUMBER()`

唯一、由 1 起算的遞增整數。

`RANK()`

由 1 起算的遞增整數。可並列，可能跳號。

`DENSE_RANK()`

由 1 起算的遞增整數。可並列，不會跳號。

RunsScored
8
7
7
6
6
3

計算列號

SELECT
    s.RunsScored,
    ROW_NUMBER() OVER (
      ORDER BY s.RunsScored DESC
    ) AS rn
FROM dbo.Scores s
ORDER BY
    s.RunsScored DESC;

RunsScored	rn
8	1
7	2
7	3
6	4
6	5
3	6

計算排名與緊密排名

SELECT
    s.RunsScored,
    RANK() OVER (
      ORDER BY s.RunsScored DESC
    ) AS rk,
    DENSE_RANK() OVER (
      ORDER BY s.RunsScored DESC
    ) AS dr
FROM dbo.Scores s
ORDER BY
    s.RunsScored DESC;

RunsScored	rk	dr
8	1	1
7	2	2
7	2	2
6	4	3
6	4	3
3	6	4

分割（PARTITION）

SELECT
    s.Team,
    s.RunsScored,
    ROW_NUMBER() OVER (
      PARTITION BY s.Team
      ORDER BY s.RunsScored DESC
    ) AS rn
FROM dbo.Scores s
ORDER BY
    s.RunsScored DESC;

Team	RunsScored	rn
AZ	8	1
AZ	6	2
AZ	3	3
FLA	7	1
FLA	7	2
FLA	6	3

彙總函式

SELECT
    s.Team,
    s.RunsScored,
    MAX(s.RunsScored) OVER (
      PARTITION BY s.Team
    ) AS MaxRuns
FROM dbo.Scores s
ORDER BY
    s.RunsScored DESC;

Team	RunsScored	MaxRuns
AZ	8	8
AZ	6	8
AZ	3	8
FLA	7	7
FLA	7	7
FLA	6	7

空視窗的彙總

SELECT
    s.Team,
    s.RunsScored,
    MAX(s.RunsScored) OVER() AS MaxRuns
FROM dbo.Scores s
ORDER BY
    s.RunsScored DESC;

Team	RunsScored	MaxRuns
AZ	8	8
AZ	6	8
AZ	3	8
FLA	7	8
FLA	7	8
FLA	6	8

一起來練習吧！

SQL Server 的時間序列分析