Question

如何获取长度为4位的id的最大值。

+--------+--------+
| id     | LName  | 
+--------+--------+
| 1234   |    ONE | 
| 123456 |    TWO |  
| 123    |  THREE |  
| 1239   |   FOUR |  
| 1233   |   FIVE |  
+--------+--------+

SELECT row 
FROM table 
WHERE id=(
    SELECT max(id) FROM table
    )

如何获取长度为4位的id的最大值。

Answer 1

select max(id) from table where ((id > 999) AND (id < 10000));

Answer 2

试试这个

select max(id) from t1 where id between 1000 and 9999;

点击on sqlfiddel

Answer 3

你可以用4种方法做到这一点

select max(id) from table where id >= 1000 AND id <= 9999;

select id from table where id >= 1000 AND id <= 9999 ORDER BY id LIMIT 0,1;

select max(id) from table where length(id) = 4;

select id from table where length(id) = 4 ORDER BY id LIMIT 0,1;

您可以检查性能（比较执行时间）。我的建议是第一次

Answer 4

SELECT * FROM table
WHERE id IN (
    SELECT MAX(id) FROM table 
    WHERE LENGTH(id) = 4
);

查询 - 使用“id”中的值长度获取最高值

4 个答案: