MYSQL：根据唯一的行值向表中添加唯一的数值？

我有这个表，我想把它分成三个表，这样我就有了名称，名称和顺序之间的关系表，第三个表只包含顺序。所以我认为一个简单的方法是在这里添加一个唯一的数字列

+----+------+-----------------------+-------+--------------+
| id | name | address               | phone | order_number |
+----+------+-----------------------+-------+--------------+
|  1 | Joe  | Joes Address          | 1111  | 1390842      |
|  2 | Paul | Pauls Address         | 2222  | 9082309      |
|  3 | Greg | Gregs Address         | 3333  | 0928340      |
|  4 | Lucy | Lucys Address         | 4444  | 9028340      |
|  5 | Paul | Pauls Address         | 2222  | 8958399      |
|  6 | Tom  | Toms Address          | 5555  | 9084024      |
|  7 | Lucy | Lucys Another Address | 4444  | 9801983      |
|  8 | Paul | Pauls Another Address | 2222  | 0982304      |
+----+------+-----------------------+-------+--------------+

我想添加一个数字列，该列具有与唯一名称值相关联的递增数字，以便得到预期的结果

+----+------+-----------------------+-------+--------------+---+
| id | name | address               | phone | order_number |NID|
+----+------+-----------------------+-------+--------------+---|
|  1 | Joe  | Joes Address          | 1111  | 1390842      | 1 |
|  2 | Paul | Pauls Address         | 2222  | 9082309      | 2 |
|  3 | Greg | Gregs Address         | 3333  | 0928340      | 3 |
|  4 | Lucy | Lucys Address         | 4444  | 9028340      | 4 |
|  5 | Paul | Pauls Address         | 2222  | 8958399      | 2 |
|  6 | Tom  | Toms Address          | 5555  | 9084024      | 5 |
|  7 | Lucy | Lucys Another Address | 4444  | 9801983      | 4 |
|  8 | Paul | Pauls Another Address | 2222  | 0982304      | 2 |
+----+------+-----------------------+-------+--------------+---+

---

我该怎么做呢？

通过使用用户定义的变量，得到一些类似于您期望的结果集的结果

select `id`, `name`, `address`, `phone`, `order_number`,
@b:= case when `name` <> @a then @b + 1 else @b end NID,
@a:= `name`
from (
    select *
    from demo b,
    (select @a:=null,@b:=1) a
    order by name 
) c

注：以上说明不能保证顺序，它将完全取决于id列值

---

如果您只想显示NID，那么@M Khalid Junaid的答案就可以了

但如果要在表中添加列NID，则以下查询将完成该工作：

alter table t
add column nid integer;

update t
set nid = (Select 
           (case when count(name)>1 then min(id)
                 else  id
            end)
           from
           (select *from t) x
           where t.name = x.name          
           );

注意：Nid不包含增量序列。它基于id列

---

希望有帮助

您只是想将NID显示为查询结果，还是想在表中添加列？

alter table t
add column nid integer;

update t
set nid = (Select 
           (case when count(name)>1 then min(id)
                 else  id
            end)
           from
           (select *from t) x
           where t.name = x.name          
           );