SQL查询连接两个表，其中第一个表行具有1-Many关系，第二个表值跟随行

Question

我需要有关以下要求的查询/ PL / SQL过程的帮助。

表格1：

T1ID      T1Name       T1Col2
 1        Name1          X
 2        Name2          Y

表2：

T2T1ID    T2SubName    T2Column2
1         Test1Sub1       P
1         Test1Sub2       P
1         Test1Sub3       P
2         Test2Sub1       Q
2         Test2Sub2       Q

我想构建一个可以获取我的查询

T1ID              T1Name              T1Col2        T2SubName      T2Column2
  1                Test1               X
                                                     Test1Sub1       P
                                                     Test1Sub2       P
                                                     Test1Sub3       P
  2                Test2               Y
                                                     Test2Sub1       Q
                                                     Test2Sub1       Q

Answer 1

任何报告工具都可以轻松实现这种“中断”布局。 在SQL * Plus中， BREAK （谁猜？）完成这项工作。 看看它是否有帮助。

SQL> break on t1id on t1name on t1col2
SQL>
SQL> with
  2  t1 (t1id, t1name, t1col2) as
  3    (select 1, 'name1', 'x' from dual union
  4     select 2, 'name2', 'y' from dual
  5    ),
  6  t2 (t2t1id, t2subname, t2column2) as
  7    (select 1, 'test1sub1', 'p' from dual union
  8     select 1, 'test1sub2', 'p' from dual union
  9     select 1, 'test1sub3', 'p' from dual union
 10     select 2, 'test2sub1', 'q' from dual union
 11     select 2, 'test2sub2', 'q' from dual
 12    )
 13  select a.t1id, a.t1name, a.t1col2, b.t2subname, b.t2column2
 14  from t1 a join t2 b on b.t2t1id = a.t1id
 15  order by a.t1id;

      T1ID T1NAM T T2SUBNAME T
---------- ----- - --------- -
         1 name1 x test1sub1 p
                   test1sub2 p
                   test1sub3 p
         2 name2 y test2sub1 q
                   test2sub2 q

SQL>

Answer 2

使用FULL OUTER JOIN和正确的ORDER BY语句：

select t1.t1id, nvl2(t1.t1name,'Test'||t1.t1id,'') t1name, t1.col2, 
       t2.t2subname, t2.t2column2 
  from table1 t1
  full outer join table2 t2
  on ( t1.col2 = t2.t2column2 )
order by nvl(t1id,2)||nvl(t2t1id,2), nvl(t2.t2subname,'0');

T1ID    T1NAME  COL2    T2SUBNAME   T2COLUMN2
----    ------  ----    ---------   ---------
 1      Test1   X       
                        Test1Sub1   P
                        Test1Sub2   P
                        Test1Sub3   P
 2      Test2   Y       
                        Test2Sub1   Q
                        Test2Sub2   Q

db <>小提琴演示