Question

我的查询结果如下所示

+-------------------+
| id | c1 | c2 | c3 |
+-------------------+
| 1  | x  | y  | z  |
+----+----+----+----+
| 1  | x  | y  | z1 |
+----+----+----+----+
| 2  | a  | b  | c  |
+----+----+----+----+
| 2  | a1 | b  | c1 |
+-------------------+

我只需要获取具有C1和c2值的记录，这些记录对于相同的id不同。

对于上面的例子，结果应为

+-------------------+
| id | c1 | c2 | c3 |
+-------------------+
| 2  | a  | b  | c  |
+----+----+----+----+
| 2  | a1 | b  | c1 |
+-------------------+

您可以帮忙查询。

Answer 1

将表连接到自身应该可行。我假设您认为C1 或 C2不同，给出您发布的示例结果。

SELECT 
  t1.id,
  t1.c1,
  t1.c2,
  t1.c3
FROM
  your_table t1 
      INNER JOIN your_table t2 ON t1.id = t2.id
WHERE
  t1.c1 <> t2.c1 OR
  t1.c2 <> t2.c2

SQLFiddle

Answer 2

这将为您提供任何与其他行不同的行。但是，如果您有3行，则可能无法正常工作。

SELECT t1.*
FROM someTable t1, someTable t2
WHERE t1.id = t2.id
   AND  (t1.c1 != t2.c1 OR t1.c2 != t2.c2)

修改

如果您只想要与具有相同ID的任何其他行不同的行，则在这种情况下第一个查询将不起作用：

+-------------------+ | id | c1 | c2 | c3 | +-------------------+ | 1 | x | y | z | +----+----+----+----+ | 1 | x | y | z1 | +----+----+----+----+ | 2 | a | b | c | +----+----+----+----+ | 2 | a1 | b | c1 | +----+----+----+----+ | 2 | a1 | b | c3 | +-------------------+

你会得到：

+-------------------+ | id | c1 | c2 | c3 | +-------------------+ | 2 | a | b | c | +----+----+----+----+ | 2 | a1 | b | c1 | +----+----+----+----+ | 2 | a1 | b | c3 | +-------------------+

我认为这是错误的。在这种情况下，您将需要以下内容：

SELECT t2.* FROM ( SELECT id, c1, c2 FROM someTable GROUP BY id, c1, c2 HAVING COUNT(*) = 1 ) t1 JOIN someTable t2 ON t2.id = t1.id AND t2.c1 = t1.c1 AND t2.c2 = t1.c2

Answer 3

如果我正确地理解了这个问题，我认为@MattGibson的答案是正确的，但如果订单很重要，则需要order by子句（按id排序）。

Answer 4

试试这个：

SELECT * FROM myTable WHERE ID 
IN(SELECT ID FROM myTable GROUP BY ID HAVING COUNT(ID)>1)

比较同一个表中的行

4 个答案: