mysql - mysql set one item id to the auto_increment max id

Question

for example,there are several items in a table

 id |name|info
 1  |Jim |Male
 2  |Rob |Male

the id of the table is auto_increment, and now i want to update Jim's row to the bottom of Rob ,and get the newest id, aka

 id |name|info
 2  |Rob |Male
 3  |Jim |Male

and get the id of (3), what's the sql expression?

score 4 · Accepted Answer

由于您无法在同一更新查询中选择 max(id)，因此您必须将 max(id) 定义为变量。您需要的查询：

SET @max = (SELECT max(`id`) FROM `table` FOR UPDATE);
UPDATE `table` SET `id` = @max+1 WHERE `name` = "Jim";

编辑：您不应该更新 id，因为它是唯一标识符。如果你想使用排序方法，你应该添加一个整数列“位置”。

score 1 · Accepted Answer

there is no update for autoincrement column you could delete Jims row and then insert it again and it will be id = 3

 DELETE FROM `table` where id = 1

then

 INSERT INTO `table` (name , info) VALUES ('jim' , 'male')

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