Question

我有一个表A和B，带有一个公共ID字段。我想在这些表上进行完全外连接，选择ID和“表A”或“表B”，具体取决于ID来自哪个表。

SELECT ID, ['tableA'|'tableB']
FROM A FULL OUTER JOIN B ON A.ID = B.ID
WHERE A.ID IS NULL OR B.ID IS NULL

Answer 1

试试这个：

SELECT  COALESCE(A.ID , B.ID) AS ID , 
       CASE  WHEN A.ID IS NOT NULL AND B.ID IS NULL THEN  <tableA results> 
             WHEN A.ID IS NULL AND B.ID IS NOT NULL THEN  <tableB results>  
       END AS results
FROM A FULL OUTER JOIN B ON A.ID = B.ID
WHERE A.ID IS NULL OR B.ID IS NULL

Answer 2

所以这是我在Tab的一点帮助后想出来的。

SELECT ID, SELECT CASE WHEN ID IN (SELECT ID FROM A) THEN 'tableA' 
                       WHEN ID IN (SELECT ID FROM B) THEN 'tableB'
FROM A FULL OUTER JOIN B ON A.ID = B.ID
WHERE A.ID IS NULL OR B.ID IS NULL

如何使用完全外连接显示动态数据？

2 个答案: