如何从oracle获取以下需求的数据？

Question

The table like this.

bh sl productdate

a1 100 2022-1-1

a1 220 2022-1-2

a1 220 2022-1-3

a2 200 2022-1-1

a2 350 2022-1-2

a2 350 2022-1-3

The result like this.

bh sl_q(sl_before) sl_h(sl_after) sl_b(changeValue) productdate

a1 100 220 120 2022-1-2

a2 200 350 150 2022-1-2

Rules:the same field bh, when the field sl change,then get the record.

Answer 1

We can use a ROW_NUMBER trick here:

WITH cte AS (
    SELECT t.*, ROW_NUMBER() OVER (PARTITION BY bh ORDER BY productdate) rn1,
                ROW_NUMBER() OVER (PARTITION BY bh ORDER BY productdate DESC) rn2
    FROM yourTable t
)

SELECT bh, MAX(CASE WHEN rn1 = 1 THEN sl END) AS sl_q,
           MAX(CASE WHEN rn2 = 1 THEN sl END) AS sl_h,
           MAX(CASE WHEN rn2 = 1 THEN sl END) - 
               MAX(CASE WHEN rn1 = 1 THEN sl END) AS sl_b
FROM cte
GROUP BY bh;