Question

我已阅读Switch id numbers of two rows in MySql和Mysql: Swap data for different rows，但我不明白。假设表格颜色如下：

------------------------------------------
| id | box | pouch  | color    | value   |
-----------------------------------------
| 1  |  1  |   1    | red      | 30      |
| 2  |  1  |   1    | blue     | 20      |
| 3  |  1  |   1    | green    | 10      |
| 4  |  1  |   1    | yellow   | 40      |
| 5  |  1  |   1    | purple   | 20      |
| 6  |  1  |   1    | black    | 50      |
| 7  |  1  |   2    | red      | 30      |
| 8  |  1  |   2    | blue     | 20      |
| 9  |  1  |   2    | green    | 10      |
| 10 |  1  |   2    | yellow   | 40      |
| 11 |  1  |   2    | purple   | 20      |
| 12 |  1  |   2    | black    | 50      |
| 13 |  2  |   1    | red      | 35      |
| 14 |  2  |   1    | blue     | 25      |
| 15 |  2  |   1    | green    | 15      |
| 16 |  2  |   1    | yellow   | 45      |
| 17 |  2  |   1    | purple   | 25      |
| 18 |  2  |   1    | black    | 55      |
| 19 |  2  |   2    | red      | 35      |
| 20 |  2  |   2    | blue     | 25      |
| 21 |  2  |   2    | green    | 15      |
| 22 |  2  |   2    | yellow   | 45      |
| 23 |  2  |   2    | purple   | 25      |
| 24 |  2  |   2    | black    | 55      |
------------------------------------------

如何交换＆＃34;值＆＃34;一行与另一行，留下＆＃34; id＆＃34;，＆＃34; box＆＃34;，＆＃34; pouch＆＃34;，＆＃34; color＆＃34;完整？

注意：我需要交换box =＆＃39; 1＆＃39;的值。带框=＆＃39; 2＆＃39; 2.行数是动态的

示例：

SWAP ROWS OF VALUE WITH BOX='1' WITH ROWS OF VALUE WITH BOX='2'

结果：

------------------------------------------
| id | box | pouch  | color    | value   |
-----------------------------------------
| 1  |  1  |   1    | red      | 35      |
| 2  |  1  |   1    | blue     | 25      |
| 3  |  1  |   1    | green    | 15      |
| 4  |  1  |   1    | yellow   | 45      |
| 5  |  1  |   1    | purple   | 25      |
| 6  |  1  |   1    | black    | 55      |
| 7  |  1  |   2    | red      | 35      |
| 8  |  1  |   2    | blue     | 25      |
| 9  |  1  |   2    | green    | 15      |
| 10 |  1  |   2    | yellow   | 45      |
| 11 |  1  |   2    | purple   | 25      |
| 12 |  1  |   2    | black    | 55      |
| 13 |  2  |   1    | red      | 30      |
| 14 |  2  |   1    | blue     | 20      |
| 15 |  2  |   1    | green    | 10      |
| 16 |  2  |   1    | yellow   | 40      |
| 17 |  2  |   1    | purple   | 20      |
| 18 |  2  |   1    | black    | 50      |
| 19 |  2  |   2    | red      | 30      |
| 20 |  2  |   2    | blue     | 20      |
| 21 |  2  |   2    | green    | 10      |
| 22 |  2  |   2    | yellow   | 40      |
| 23 |  2  |   2    | purple   | 20      |
| 24 |  2  |   2    | black    | 50      |
------------------------------------------

有人有想法吗？感谢

Answer 1

创建一个包含您要交换的所有值的表。

 create table tmp_t as select * from t;

然后两次更新你的桌子：

update t t1 
inner join tmp_t t2 on t1.color = t2.color 
                    and t1.pouch = t2.pouch 
                    and t1.box = 1 and t2.box = 2 
set t1.value = t2.value;

update t t1 
inner join tmp_t t2 on t1.color = t2.color 
                    and t1.pouch = t2.pouch 
                    and t1.box = 2 and t2.box = 1 
set t1.value = t2.value;

就是这样。看到它在sqlfiddle中正常工作。

Answer 2

要进行交换，请尝试将其中一个重置为临时值。您需要这样做，否则第二次更新将影响第一次更新。

UPDATE mytable SET box = -1 WHERE box = 1; -- Set box 1 to a temporary value
UPDATE mytable SET box = 1 WHERE box = 2; -- Set box 2 to box 1
UPDATE mytable SET box = 2 WHERE box = -1; -- Set box 1 to box 2

我认为不可能有负箱号。如果允许-1，请使用其他内容，例如null。

为了更加安全，请在事务中包含上述内容，因此如果出现任何问题，您可以回滚。

Mysql：如何在行之间交换一列的数据？

2 个答案: