如何获取来自 MySQL 表的新增记录?
为此,你可以将 ORDER BY 与 LIMIT 配合使用。此处,LIMIT 用来设置要获取的记录的限制(计数)。我们先创建一个表 −
mysql> create table DemoTable1486 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.66 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1486(StudentName) values('Chris Brown'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1486(StudentName) values('David Miller'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1486(StudentName) values('John Doe'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1486(StudentName) values('John Smith'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1486(StudentName) values('Adam Smith'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1486(StudentName) values('Carol Taylor'); Query OK, 1 row affected (0.16 sec)
使用 select 语句从表中显示所有记录 −
mysql> select * from DemoTable1486;
这将生成以下输出 −
+-----------+--------------+ | StudentId | StudentName | +-----------+--------------+ | 1 | Chris Brown | | 2 | David Miller | | 3 | John Doe | | 4 | John Smith | | 5 | Adam Smith | | 6 | Carol Taylor | +-----------+--------------+ 6 rows in set (0.00 sec)
以下是对获取新增记录的查询 −
mysql> select * from DemoTable1486 -> order by StudentId desc -> limit 3;
这将生成以下输出 −
+-----------+--------------+ | StudentId | StudentName | +-----------+--------------+ | 6 | Carol Taylor | | 5 | Adam Smith | | 4 | John Smith | +-----------+--------------+ 3 rows in set (0.00 sec)
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