Oracle ：基于期间的先前记录获取价值

【问题标题】：Oracle :Get Value based on a previous record based on periodOracle ：基于期间的先前记录获取价值
【发布时间】：2015-05-22 12:18:59
【问题描述】：

出于安全原因，我删除了表名。对不起

【问题讨论】：

标签： sql oracle window-functions

【解决方案1】：

您需要指定lag 以分别处理每个pgm_id，并带有partition by 子句：

CREATE OR REPLACE FORCE VIEW HCRS.PGM_MEDI_LIVES_V
(
   PGM_ID,
   PERIOD_ID,
   MEDI_COV_LIVES,
   PREV_MEDI_COV_LIVES
)
AS
   SELECT 
         pgm_id,
         pml.period_id,
         medi_cov_lives,
         LAG (medi_cov_lives, 1, 0)
             OVER (PARTITION BY pml.pgm_id ORDER BY pml.period_id)
             AS pre_medi_cov_lives
     FROM PGM_MEDI_LIVES pml;

【讨论】：

【解决方案2】：

我觉得你需要加partition by:

SELECT pgm_id, pml.period_id, medi_cov_lives,
       LAG(medi_cov_lives, 1, 0)
          OVER (PARTITION BY pgm_id ORDER BY pml.pgm_id, pml.period_id
               ) AS pre_medi_cov_lives
FROM <table> pml;

【讨论】：