的MySQL：在多个领域寻找重复

Question

比方说，我有以下五个记录表中的一个MySQL数据库：

ID: 1 
Field1: A 
Field2: B 
Field3: C 

ID: 2 
Field1: D 
Field2: E 
Field3: F 

ID: 3 
Field1: A 
Field2: H 
Field3: I 

ID: 4 
Field1: J 
Field2: K 
Field3: A 

ID: 5 
Field1: M 
Field2: D 
Field3: O 

请注意，下面的值是重复的：

ID 1，场1具有相同的值作为ID 3，场1和ID 4，字段3

ID 2，场1具有相同的值的ID 5，场2

是否有一个SELECT语句第在哪里可以找到所有上述重复？

Answer 1

它是可行的，但不知道这是否是任何不仅仅是做它在应用层面更有效：

你的表：

mysql> select * from test; 
+----+--------+--------+--------+ 
| id | field1 | field2 | field3 | 
+----+--------+--------+--------+ 
| 1 | A  | B  | C  | 
| 2 | D  | E  | F  | 
| 3 | A  | H  | I  | 
| 4 | J  | K  | A  | 
| 5 | M  | D  | O  | 
+----+--------+--------+--------+ 
5 rows in set (0.00 sec) 

选择寻找受骗者：

mysql> select count(value) as dupe_count,value from (select field1 as value from test union all select field2 from test union all select field3 from test) as tbl group by value having count(value) > 1 order by 1 desc; 
+------------+-------+ 
| dupe_count | value | 
+------------+-------+ 
|   3 | A  | 
|   2 | D  | 
+------------+-------+ 
2 rows in set (0.00 sec) 

基本上你把三根柱联成一体然后找模具