需要将当前版本的FROM_DT更新为同一个表的先前版本TO_DATE

Question

要求如下：在同一个表中我需要如下预期输出。 表名：TAB 电流输出：

PRIM_KEY| FROM_DT  |  TO_DT
11111     01-JAN-00   01-JAN-25
11112     01-MAR-16   01-JAN-25

期待输出：

PRIM_KEY| FROM_DT  |  TO_DT
11111     01-JAN-00   01-MAR-16
11112     01-MAR-16   01-JAN-25

Answer 1

你可以使用窗口函数并只关注行跟随，最后一行将为null，你可以跳过它。

MERGE
 INTO table1 AS A
 USING 
     (
    SELECT PRIM_KEY, FROM_DT, MIN(FROM_DT) OVER ( PARTITION BY 1 ORDER   BY  PRIM_KEY  ROWS BETWEEN 1 FOLLOWING AND 1 FOLLOWING) AS NEXT_START_DT
    FROM table1) AS B
    ON A.PRIM_KEY = B.PRIM_KEY AND B. PRIM_KEY IS NOT NULL
   WHEN MATCHED THEN
  UPDATE SET TO_DT = NEXT_START_DT;