從具有相同主鍵但不同值的兩個表中選擇一個表？

Question

Table1   Table2 

id | name  id | name 
-----------  ------------ 
2 | A   2 | E 
4 | B   3 | F 
6 | C   4 | G 
8 | D   5 | H  

輸出：

Id | name 
------------ 
2 | A *** E 
4 | B *** G 
6 | C *** EMPTY 
8 | D *** EMPTY 
3 | EMPTY *** F 
5 | EMPTY *** H 

Answer 1

您沒有指定一個數據庫管理系統，所以這是ANSI SQL：

select coalesce(t1.id, t2.id) as id, 
     t1.name, 
     t2.name 
from table1 t1 
    full outer join table2 t2 on t1.id = t2.id 
where t1.name is distinct from t2.name; 

Answer 2

select isnull(a.id, b.id), case when a.value is not null and b.value is not null then a.value + '***' + b.value 

其他COALESCE（a.value中，b.value）結束from table_1 a.id = b.id上的完整外部聯接table_2 b