按字段创建订单号组

Question

所以我将这些数据存储在mysql中：

|  name  |  number  |  group  |
-------------------------------
| godard |          |    1    |
| gaylord|          |    1    |
| linda  |          |    1    |
| demi   |          |    2    |
| micha  |          |    2    |

我想按组字段插入订单号。所以表格如下：

|  name  |  number   |  group  |
-------------------------------
| godard |     1     |    1    |
| gaylord|     2     |    1    |
| linda  |     3     |    1    |
| demi   |     1     |    2    |
| micha  |     2     |    2    |

我可以在mysql中执行此操作：

Answer 1

您可以使用以下查询来完成此操作。

SET @a = 1; 
SET @past = '';

CREATE TEMPORARY TABLE IF NOT EXISTS `temp_test` (
    `name` VARCHAR(50) NULL DEFAULT NULL,
    `group` TINYINT(4) NULL DEFAULT NULL,
    `number` TINYINT(4) NULL DEFAULT NULL
)
SELECT t.name as name, if(@past = t.`group`, @a:= @a + 1, @a:= 1) as             
number, @past:= t.`group` as 'group'
FROM test t
ORDER BY t.`group`;

UPDATE test
INNER JOIN temp_test ON test.name = temp_test.name AND test.`group` =     temp_test.`group` SET test.number = temp_test.number WHERE test.number IS NULL OR test.number = 0 OR test.number = '';

DROP TEMPORARY TABLE IF EXISTS temp_test;

Answer 2

检查这个。

@row_num变量保存当前行号，@ pev_value变量保存分区的当前值。

UPDATE TEMP T join 

(select o.Name,@row_num := IF(@prev_value=o.group,@row_num+1,1) AS Number
      ,@prev_value := o.group AS `Group`
      from temp o ,
      (SELECT @row_num := 1) x,
      (SELECT @prev_value := '') y
 )a on a.name=T.name and a.`group` =T.`group` 
SET T.number = a.Number\\

select * from temp

Demo Link

  

OutPut：

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