的MySQL：在多個領域尋找重複

Question

比方說，我有以下五個記錄表中的一個MySQL數據庫：

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 

請注意，下面的值是重複的：

ID 1，場1具有相同的值作爲ID 3，場1和ID 4，字段3

ID 2，場1具有相同的值的ID 5，場2

是否有一個SELECT語句第在哪裏可以找到所有上述重複？

Answer 1

它是可行的，但不知道這是否是任何不僅僅是做它在應用層面更有效：

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) 

選擇尋找受騙者：

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) 

基本上你把三根柱聯成一體然後找模具