oracle - 如何找到有条件的两行之间的差异

Question

name      point
----------
steve     207
Mary      203
steve     205
steve     200
steve     139
Mary      300

我想得到条件 eqn = [ (row + 1) - row] 其中 name = steve 的行之间的差异，所以我理想情况下希望它是，

steve 2   //207 - 0
steve 5   //205 - 207
steve 61  //200 - 205
steve 139 //139 - 200

有代码可用于查找连续行之间的差异。但是添加条件时它将不起作用。

Answer 1

已编辑应有的 OP 评论我已更改查询以完全匹配您的请求。

LAG可以帮助您：

  select name, 
    coalesce( 
        point - lag( point , 1, Null ) over (order by point),
        point)
    as diff,
    point || '-' ||
    LEAD( point , 1, 0 ) over (order by point) as prev_point
  from t   
  where name = 'steve'  
  order by point desc

结果：

|  NAME | DIFF | PREV_POINT |
-----------------------------
| steve |    2 |      207-0 |
| steve |    5 |    205-207 |
| steve |   61 |    200-205 |
| steve |  139 |    139-200 |