Question

我一直在尝试开发一个查询来解决问题，但一直很难。

表1：

+------+----+
| NAME | ID |
+------+----+
| A    |  1 |
| A    |  2 |
| B    |  1 |
| B    |  5 |
| C    |  8 |
+------+----+

表2：

+------+----+
| NAME | ID |
+------+----+
| A    |  1 |
| A    |  4 |
| B    |  3 |
| B    |  5 |
| D    |  9 |
+------+----+

从这些结果中，我需要返回表2中名称中包含的所有内容，而不需要返回ID。

所以，这个例子，返回应该是：

+------+----+
| NAME | ID |
+------+----+
| A    |  4 |
| B    |  3 |
+------+----+

Answer 1

你可能想试试这个：

编辑：用WITH子句中的简单子查询替换table1和table2。

WITH table1 AS
(
SELECT
  DECODE(LEVEL,1, 'A',2, 'A',3, 'B',4, 'B',5, 'C') AS name
  ,DECODE(LEVEL,1, 1,2, 2,3, 1,4, 5,5, 8) AS id
FROM
  dual
CONNECT BY LEVEL < 6
)
,table2 AS
(
SELECT
  DECODE(LEVEL,1, 'A',2, 'A',3, 'B',4, 'B',5, 'D') AS name
  ,DECODE(LEVEL,1, 1,2, 4,3, 3,4, 5,5, 9) AS id
FROM
  dual
CONNECT BY LEVEL < 6
)
SELECT
  t2.id
  ,t2.name
FROM
  table1 t1
  ,table2 t2
WHERE
  t1.name = t2.name -- here we take all the records from table2, which have the same names as in table1
MINUS -- then we "subtract" the records that have both the same name and id in both tables
SELECT
  t2.id
  ,t2.name
FROM
  table1 t1
  ,table2 t2
WHERE
  t1.name = t2.name
  AND t1.id = t2.id

Answer 2

我愿意：

with t1 as (select 'A' name, 1 id from dual union all
            select 'A' name, 2 id from dual union all
            select 'B' name, 1 id from dual union all
            select 'B' name, 5 id from dual union all
            select 'C' name, 8 id from dual),
     t2 as (select 'A' name, 1 id from dual union all
            select 'A' name, 4 id from dual union all
            select 'B' name, 3 id from dual union all
            select 'B' name, 5 id from dual union all
            select 'D' name, 9 id from dual)
select name, id
from   t2
where  name in (select name from t1)
minus
select name, id
from   t1;

NAME         ID
---- ----------
A             4
B             3

Answer 3

您可以使用NOT EXISTS或类似的东西：

SELECT  t2.*
FROM Table2 t2
WHERE NOT EXISTS
(
   SELECT 1
   FROM Tabl1 t1
   WHERE t1.Name = t2.Name
   AND t1.Id = t2.Id
);

Answer 4

SELECT T1.ID,T1.NAME
FROM TABLE2 T1 INNER JOIN TABLE1 T2 ON T1.NAME = T2.NAME
               LEFT JOIN TABLE1 T3 ON T3.ID = T1.ID
WHERE T3.ID IS NULL

从表2返回表1中相同名称的不同ID

4 个答案: