使用 SQL 在 table 的每组记录中创建自定义记录。基于场景

Question

Tab_X

**Col_1 Col_2   Col_3**
A1      B1      10
A1      B2      7
A2      B1      15
A2      B2      6

输出

**Col_1 Col_2   Col_3** 
A1      B1      10  
A1      B2      7   
**A1        null            3    {10 - 7}**
A2      B1      15  
A2      B2      6   
**A2        Null            9   {15 - 6}**

Col_1 的所有组都应该有一条新记录 col_3 值如下 = Col_3 {其中 col_2 = ‘B1’} - SUM(Col_3) {其中 col_2 <> ‘B1’}

有人可以建议 SQL 实现这个吗？

Answer 1

with Tab_X (Col_1, Col_2, Col_3) as (
    select 'A1', 'B1', 10 from dual union all
    select 'A1', 'B2', 7  from dual union all
    select 'A2', 'B1', 15 from dual union all
    select 'A2', 'B2', 6  from dual
)
select *
from Tab_X
union all -- UPDATE, thanks @GordonLinoff
select Col_1
     , null
     , sum(Col_3 * case when Col_2 = 'B1' then 1 else -1 end)
from Tab_X
group by Col_1;

评论：

请在您的输入说明中使用 CTE（with 子句）以便回答更方便
请标记数据库供应商的问题。从 plsql 标签我猜你有 Oracle 不幸的是没有 filter (where) 子句，因此 sum (case when) 解决方法
也可以使用 group by rollup 解决，但我想不出来

更新：基于group by rollup

的解决方案

with Tab_X (Col_1, Col_2, Col_3) as (
    select 'A1', 'B1', 10 from dual union all
    select 'A1', 'B2', 7  from dual union all
    select 'A2', 'B1', 15 from dual union all
    select 'A2', 'B2', 6  from dual
)
select Col_1
     , null
     , case
         when grouping(Col_2) = 1 then sum(Col_3 * case when Col_2 = 'B1' then 1 else -1 end)
         else min(Col_3)
       end as Col_3
from Tab_X
group by Col_1, rollup (Col_2)

Answer 2

我对前一行的 col_3 值使用了 "lag" 函数。并且 "Rank" 列用于捕获更改 col_1 列（A1 到 A2）。当它更改时，排名会增加。

with tab_x (col_1, col_2, col_3)
 as (select 'A1', 'B1', 10 from DUAL
     union
     select 'A1', 'B2', 7 from DUAL
     union
     select 'A2', 'B1', 15 from DUAL
     union
     select 'A2', 'B2', 6 from DUAL)  select x.col_1, x.col_2, x.col_3
from (select col_1,
             col_2,
             col_3,
             null RANK
        from (select col_1,
                     null col_2,
                     LAG (col_3, 1, 0) over (order by col_1) - col_3
                        as col_3,
                     null,
                     RANK ()
                        over (partition by col_1 order by col_1, col_2)
                        RANK
                from tab_x)
       where RANK = 2
      union all
      select col_1,
             col_2,
             col_3,               
             null RANK
        from tab_x
      order by col_1, col_2) x order by col_1, col_2

使用 SQL 在 table 的每组记录中创建自定义记录。基于场景

Creating customised records in each group of records in table using SQL. Scenario based

sql

plsql

scenarios