就业数据 - Pivot table，将所有就业数据放在一行中

Question

你好，我 table 如下

employee id	job	start_dt
1	abc	1/1/2021
1	def	5/1/2021
2	xyz	6/1/2021
2	rfd	8/1/2021
2	hgf	7/1/2021
2	esd	1/1/1999

我想知道是否有一种方法可以旋转 table 并将所有工作和日期放在同一行，

employee id	job_a	start_dt_ a	job_b	start_dt_b	job_c	start_dt_c	job_d	start_dt_d	job_e	start_dt_e	job_f	start_dt_f
1	abc	1/1/2021	def	5/1/2021
2	xyz	6/1/2021	rfd	8/1/2021	hgf	7/1/2021	esd	1/1/1999

(table 姓名 'JOB')

Answer 1

您可以使用条件聚合以及ROW_NUMBER()分析函数，例如

WITH j AS
(  
 SELECT ROW_NUMBER() OVER (PARTITION BY employee_id ORDER BY start_dt) AS rn,
        j.*
   FROM job j
)
SELECT employee_id, 
       MAX(CASE WHEN rn = 1 THEN job END) AS job_a,
       MAX(CASE WHEN rn = 1 THEN start_dt END) AS start_dt_a,  
       MAX(CASE WHEN rn = 2 THEN job END) AS job_b,
       MAX(CASE WHEN rn = 2 THEN start_dt END) AS start_dt_b,
       MAX(CASE WHEN rn = 3 THEN job END) AS job_c,
       MAX(CASE WHEN rn = 3 THEN start_dt END) AS start_dt_c,
       MAX(CASE WHEN rn = 4 THEN job END) AS job_d,
       MAX(CASE WHEN rn = 4 THEN start_dt END) AS start_dt_d              
  FROM j
 GROUP BY employee_id
 ORDER BY employee_id

Demo

P.S。 当前结果集排序逻辑不够清晰

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