你是在寻找领先还是落后 Windows function ，但mysql支持的版本高于8.0。因此，您可以在 select 像这样。
测试DLL

CREATE TABLE T(
   ID int,
   Name VARCHAR(100),
   `Group` VARCHAR(5)
);

INSERT INTO T VALUES (1,'One','A');
INSERT INTO T VALUES (2,'Two','B');
INSERT INTO T VALUES (3,'Three','A');
INSERT INTO T VALUES (4,'Fore','C');
INSERT INTO T VALUES (5,'Five','B');
INSERT INTO T VALUES (6,'Six','A');
INSERT INTO T VALUES (7,'Seven','B');

查询

select *,IFNULL((
          SELECT t2.ID
          FROM T t2 
          WHERE t1.Group = t2.Group and t1.ID > t2.ID 
          ORDER BY t2.ID DESC
          LIMIT 1
         ),t1.ID)previousID
         ,IFNULL((
          SELECT t2.ID
          FROM T t2 
          WHERE t1.Group = t2.Group and t1.ID < t2.ID 
          ORDER BY t2.ID 
          LIMIT 1
         ),t1.ID) nextID
from T t1

[结果]：

| ID |  Name | Group | previousID | nextID |
|----|-------|-------|------------|--------|
|  1 |   One |     A |          1 |      3 |
|  2 |   Two |     B |          2 |      5 |
|  3 | Three |     A |          1 |      6 |
|  4 |  Fore |     C |          4 |      4 |
|  5 |  Five |     B |          2 |      7 |
|  6 |   Six |     A |          3 |      6 |
|  7 | Seven |     B |          5 |      7 |

如果你的mysql支持windows函数，你可以试试这个。

select *,
  LAG(ID)previousID,
  LEAD(ID) nextID
from T

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