我需要从我的其中一个表格中删除所有重复的记录,但问题是没有任何id、唯一或键列,因此我无法像这样做:
delete from tbl using tbl,tbl t2 where tbl.locationID=t2.locationID
and tbl.linkID=t2.linkID and tbl.ID>t2.ID
因为需要一个id列或唯一键列,所以我无法创建。
ALTER IGNORE TABLE 'mytable' ADD UNIQUE INDEX
因为有些信息需要始终重复使用,而其他信息则不需要。但我无法做到这一点:
DELETE FROM 'table' WHERE 'field' IN (SELECT 'field' FROM 'table' GROUP BY 'field'HAVING (COUNT('field')>1))
因为它将删除所有重复的,并且永远不会留下一个。 这是我的表格示例。
+----------+----------------------+-------------+-------------+
| phone | address | name | cellphone |
+----------+----------------------+-------------+-------------+
| 2555555 | 1020 PANORAMA | JUAN CARLOS | 0999999999 | diferent address
| 2555555 | GABRIEL JOSE 1020 | JUAN CARLOS | 0999999999 | good one
| 2555555 | GABRIEL JOSE 1020 | JUAN CARLOS | 0999999999 | duplicated
| 2555555 | C ATARAZANA 1020 | SILVIA | 0777777777 | another good one
| 2555555 | C ATARAZANA 1020 | SILVIA | 0777777777 | another duplicated
| 2555555 | GABRIEL JOSE 1020 | VIOLETA | 0888888888 | diferent person
+----------+----------------------+-------------+-------------+
and this is what I want to leave
+----------+----------------------+--------------+-------------+
| phone | address | name | cellphone |
+----------+----------------------+--------------+-------------+
| 2555555 | 1020 PANORAMA | JUAN CARLOS | 0999999999 |
| 2555555 | GABRIEL JOSE 1020 | JUAN CARLOS | 0999999999 |
| 2555555 | C ATARAZANA 1020 | SILVIA | 0777777777 |
| 2555555 | GABRIEL JOSE 1020 | VIOLETA | 0888888888 |
+----------+----------------------+--------------+-------------+
我不能截断或删除原始表,因为它在24/7使用并且有10000000条记录...
请帮帮我。