MYSQL自动编号组

Question

我有一些情况，例如：

查询：

set @rank = 0;
select @rank:=@rank+1, CONCAT_WS(" ",`Group`, SubGroup, TertiaryGroup) Items,ItemGroup, item from myTable

这是我的示例文本数据

项目：

A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:   
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:   
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       
A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       
A. CARRIER: 1. UNDERCARRIAGE: 1.2 Final Drive System Condition:         
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:   
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition: 
A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:   
A. CARRIER: 1. UNDERCARRIAGE: 1.4 Underchassis Condition:       
A. CARRIER: 1. UNDERCARRIAGE: 1.4 Underchassis Condition:   
A. CARRIER: 1. UNDERCARRIAGE: 1.4 Underchassis Condition:   
B. ENGINE SYSTEM Condition:     
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         
B. ENGINE SYSTEM Condition:         

只有这些东西对我来说足够了，谢谢

但是我需要一个结果，如果项目不同或已更改，则自动编号的计数会从1开始倒数。

就像从我的样本图像结果来看，数字10必须返回1 ，下一个必须再次返回1,2,3,4 ，依此类推。

仅items列而不是item

可能吗？

提前致谢。

Answer 1

假设您有一种排序数据的方式（例如auto_increment id列），则可以

insert into t (items)  values
('A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:'),
('A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:' )  ,
('A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:'),       
('A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:' ) ,    
('A. CARRIER: 1. UNDERCARRIAGE: 1.2 Final Drive System Condition:')  ,       
('A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:'),
('A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:' ),
('B. ENGINE SYSTEM Condition:') ,   
('B. ENGINE SYSTEM Condition:' ) ;

select items ,
            if(items <> @p,@rn:=1,@rn:=@rn+1) rn,
            @p:=items previousitem
from t
cross join (select @rn:=0,@p:='') r
order by id;

+-----------------------------------------------------------------+------+-----------------------------------------------------------------+
| items                                                           | rn   | previousitem                                                    |
+-----------------------------------------------------------------+------+-----------------------------------------------------------------+
| A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |    1 | A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |
| A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |    2 | A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |
| A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |    3 | A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |
| A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |    4 | A. CARRIER: 1. UNDERCARRIAGE: 1.1 Track System Condition:       |
| A. CARRIER: 1. UNDERCARRIAGE: 1.2 Final Drive System Condition: |    1 | A. CARRIER: 1. UNDERCARRIAGE: 1.2 Final Drive System Condition: |
| A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:       |    1 | A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:       |
| A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:       |    2 | A. CARRIER: 1. UNDERCARRIAGE: 1.3 Transmission Condition:       |
| B. ENGINE SYSTEM Condition:                                     |    1 | B. ENGINE SYSTEM Condition:                                     |
| B. ENGINE SYSTEM Condition:                                     |    2 | B. ENGINE SYSTEM Condition:                                     |
+-----------------------------------------------------------------+------+-----------------------------------------------------------------+
9 rows in set (0.00 sec)

Answer 2

尝试这个：

set @rank = 0; set @key = ''; SELECT IF( CONCAT_WS(" ",`Group`, SubGroup, TertiaryGroup) = @key, @rank:=@rank+1, 1 ), @key:=CONCAT_WS(" ",`Group`, SubGroup, TertiaryGroup) Items,ItemGroup, item FROM myTable