modifikasi data mysql - duplikasi data, reindex, merge data

menghapus data duplikat di mysql

Contoh Data:

+----+--------+
| id | name   |
+----+--------+
| 1  | google |
| 2  | yahoo  |
| 3  | msn    |
| 4  | google |
| 5  | google |
| 6  | yahoo  |
+----+--------+

Jika Anda ingin menyimpan baris dengan nilai id terendah:

DELETE FROM NAMES
 WHERE id NOT IN (SELECT * 
                    FROM (SELECT MIN(n.id)
                            FROM NAMES n
                        GROUP BY n.name) x)

Jika Anda ingin menyimpan baris dengan nilai id tertinggi:

DELETE FROM NAMES
 WHERE id NOT IN (SELECT * 
                    FROM (SELECT MAX(n.id)
                            FROM NAMES n
                        GROUP BY n.name) x)

sumber : http://stackoverflow.com/questions/4685173/delete-all-duplicate-rows-except-for-one-in-mysql

reindex id setelah proses penghapusan data yang duplikat ^^

SET @newid=0;
UPDATE tablename SET primary_key_id=(@newid:=@newid+1) ORDER BY primary_key_id;

isi tablename = nama tabel, primary_key_id = id

sumber : http://stackoverflow.com/questions/10242311/query-to-re-index-primary-key-of-mysql-database

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