获取 MySQL 表中的最后一项?
mysqlmysqli database
您可以使用 ORDER BY 获取 MySQL 表中的最后一项。第一种方法如下:
案例 1:使用 DESC LIMIT
SELECT * FROM yourTableName ORDER BY yourColumnName DESC LIMIT 1;
第二种方法如下:
Case 2: Using MAX()
SET @anyVariableName = (SELECT MAX(yourColumnName) FROM yourTableName); SELECT *FROM yourtableName WHERE yourColumnName = @anyVariableName;
现在，为了理解这两种方法，让我们创建一个表。创建表的查询如下:
mysql> create table lastEntryDemo -> ( -> Id int NOt NULL AUTO_INCREMENT, -> Name varchar(30), -> Age int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.71 sec)
使用 insert 命令在表中插入一些记录。 查询语句如下:
mysql> insert into lastEntryDemo(Name,Age) values('Larry',24);
Query OK, 1 row affected (0.14 sec)
mysql> insert into lastEntryDemo(Name,Age) values('John',21);
Query OK, 1 row affected (0.19 sec)
mysql> insert into lastEntryDemo(Name,Age) values('David',22);
Query OK, 1 row affected (0.18 sec)
mysql> insert into lastEntryDemo(Name,Age) values('Bob',25);
Query OK, 1 row affected (0.20 sec)
mysql> insert into lastEntryDemo(Name,Age) values('Carol',29);
Query OK, 1 row affected (0.17 sec)
mysql> insert into lastEntryDemo(Name,Age) values('Mike',23);
Query OK, 1 row affected (0.14 sec)
mysql> insert into lastEntryDemo(Name,Age) values('Sam',20);
Query OK, 1 row affected (0.15 sec)
使用 select 语句显示表中的所有记录。查询如下:
mysql> select *from lastEntryDemo;
输出结果如下:
+----+-------+------+ | Id | Name | Age | +----+-------+------+ | 1 | Larry | 24 | | 2 | John | 21 | | 3 | David | 22 | | 4 | Bob | 25 | | 5 | Carol | 29 | | 6 | Mike | 23 | | 7 | Sam | 20 | +----+-------+------+ 7 rows in set (0.00 sec)
以下是使用 ORDER BY 获取最后一个条目的查询。
案例 1:DESC LIMIT
查询如下:
mysql> select *from lastEntryDemo order by Name desc limit 1;
输出结果如下:
+----+------+------+ | Id | Name | Age | +----+------+------+ | 7 | Sam | 20 | +----+------+------+ 1 row in set (0.00 sec)
案例 2:使用 MAX()
查询如下:
mysql> set @MaxId = (select max(Id) from lastEntryDemo); Query OK, 0 rows affected (0.00 sec) mysql> select *from lastEntryDemo where Id = @MaxId;
输出结果如下:
+----+------+------+ | Id | Name | Age | +----+------+------+ | 7 | Sam | 20 | +----+------+------+ 1 row in set (0.00 sec)
