Question

我想写一个sql，它给出了以下结果。这可能吗？我尝试使用UNION但它只适用于一条记录。

col1  | col2 | col3 | col4 
---------------------------
  A   |  10  |      |
      |   2  | val1 | val2  
      |   5  | val3 | val4
      |   3  | val5 | val6
  B   |  11  |      |
      |   3  | val7 | val8  
      |   5  | val9 | val10
      |   3  | val0 | val12

这是我的查询：

SELECT a.val1, NULL val2, a.val3 FROM table1 a 
WHERE a.val1 = 'A' 
UNION 
SELECT NULL val1, b.val2, b.val3 FROM table2 b 
WHERE b.val1 = 'A' ;

也许这会使问题更清楚。

想象一下，如果我运行查询：

SELECT a.val1, NULL val2, a.val3 FROM table1 a 
UNION 
SELECT NULL val1, b.val2, b.val3 FROM table2 b ;

我希望结果集如上图所示。

col1  | col2 | col3 | col4 
---------------------------
  A   |  10  |      |
      |   2  | val1 | val2  
      |   5  | val3 | val4
      |   3  | val5 | val6
  B   |  11  |      |
      |   3  | val7 | val8  
      |   5  | val9 | val10
      |   3  | val0 | val12

Answer 1

汇总或常规群组可以执行此操作，但您仍未考虑col2。它来自哪里，就像你的sql片段一样，你根本就没有它。

SQL> create table yourtab(col1, col2, col3, col4)
  2  as
  3  select 'A', 2, 'val1', 'val2' from dual
  4  union all select 'A', 5, 'val3', 'val4' from dual
  5  union all select 'A', 3, 'val5', 'val6' from dual
  6  union all select 'B', 3, 'val7', 'val8' from dual
  7  union all select 'B', 5, 'val9', 'val10' from dual
  8  union all select 'B', 3, 'val11', 'val12' from dual;

Table created.

SQL>
SQL> select col1, sum(col2) col2, col3, col4
  2    from yourtab
  3   group by col1, rollup(col3, col4)
  4  having (grouping_id(col3), grouping_id(col4)) in ((0,0),(1,1))
  5  order by col1, grouping_id(col3) desc;

C       COL2 COL3  COL4
- ---------- ----- -----
A         10
A          5 val3  val4
A          3 val5  val6
A          2 val1  val2
B         11
B          3 val7  val8
B          5 val9  val10
B          3 val11 val12

8 rows selected.

SQL>
SQL> select col1, col2, col3, col4
  2    from (select col1, col2, col3, col4, 2 grp
  3            from yourtab
  4          union all
  5          select col1, sum(col2), null, null, 1 grp
  6            from yourtab
  7           group by col1)
  8   order by col1, grp;

C       COL2 COL3  COL4
- ---------- ----- -----
A         10
A          5 val3  val4
A          3 val5  val6
A          2 val1  val2
B         11
B          3 val11 val12
B          5 val9  val10
B          3 val7  val8

8 rows selected.

SQL自定义选择

1 个答案: