Mysql Find Duplicate Records

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Mysql Find Duplicate Records

Mysql Find Duplicate Records is used to find the duplicate Records in the table.

Mysql Find Duplicate Records is used to find the duplicate Records in the table.

Mysql Find Duplicate Records

     

Mysql Find Duplicate Records is used to find the duplicate Records in the table.

Understand with Example

The Tutorial illustrate an example from 'Mysql Find Duplicate Records'. To grasp and understand example, the select query is used to return the records from table 'employee12'.

 select * from employee12;

Table structure:

+-------+----------+--------+------------+
| Empid | Empname  | Salary | DOB        |
+-------+----------+--------+------------+
|     1 | Habib    |   2014 | 2004-12-02 |
|     2 | Karan    |   4021 | 2003-04-11 |
|     3 | Samia    |     22 | 2008-02-23 |
|     4 | Hui Ling |     25 | 2008-10-15 |
|     5 | Yumie    |     29 | 1999-01-26 |
|    10 | NULL     | 210000 | 2009-01-12 |
|    10 | jjlkl    |   2222 | 2008-02-13 |
|    10 | hkjkkjl  |   2222 | 2008-02-14 |
+-------+----------+--------+------------+

Query for finding duplicate records:

The Query is used to find the maximum number of duplicate records

mysql> SELECT *, count(*) as n
    ->  FROM employee12
    ->  group by empid
    ->  HAVING n>1;

Output:-

+-------+---------+--------+------------+---+
| Empid | Empname | Salary | DOB        | n |
+-------+---------+--------+------------+---+
|    10 | NULL    | 210000 | 2009-01-12 | 3 |
+-------+---------+--------+------------+---+
1 row in set (0.00 sec)

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