[英]How to delete and insert serial-num in MYSQL and also reorder serial-num?
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| id | name |
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| 1 | Ali |
| 2 | ahmd |
| 3 | jada |
| 4 | nisr |
| 5 | sara |
| 6 | mona |
| 7 | dana |
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I want to re-order ID when I delete any row like id=5 and be like that => 我想在删除ID = 5之类的任何行时重新排序ID,就像这样=>
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| id | name |
===============
| 1 | Ali |
| 2 | ahmd |
| 3 | jada |
| 4 | nisr |
| 5 | mona |
| 6 | dana |
===============
also the same this if I insert a row with id=2 name=yafa, how to re-order the table without duplicate any value and to be like that 如果我插入id = 2 name = yafa的行,也是如此,如何在不重复任何值的情况下重新排序表,就像这样
| id | name |
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| 1 | Ali |
| 2 | yafa |
| 3 | ahmd |
| 4 | jada |
| 5 | nisr |
| 6 | sara |
| 7 | mona |
| 8 | dana |
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This is assuming you always know what 'id' you are adding or deleting. 这是假设您始终知道要添加或删除的“ id”。 (Also, you always work with only one row at a time). (此外,您一次始终只能处理一行)。
For a delete: 对于删除:
DELETE FROM tableName WHERE id = 5;
UPDATE tableName
SET id = id-1
WHERE id > 5;
For an insert: 对于插入:
UPDATE tableName
SET id = id + 1
WHERE id >= 2;
INSERT INTO tableName (id, name) VALUES (2, 'yafa');
Btw, why would you want to do this. 顺便说一句,你为什么要这样做。 Set the column 'id' to be an auto-increment field and let the database deal with it. 将列“ id”设置为自动递增字段,并由数据库处理。 Do you care if you are skipping numbers ? 您是否要跳过数字?
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