MySQL select order by 的作用类似于字符串(而不是数字)?
mysqlmysqli database
如果您的列具有 varchar 数据类型，则可以使用以下语法 −
select yourColumnName FROM yourTableName ORDER BY yourColumnName +0 DESC;
为了理解上述语法，让我们创建一个表。创建表的查询如下 −
mysql> create table selectOrderdemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(100), -> RankNumber varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)
使用 insert 命令在表中插入一些记录。 查询语句如下 −
mysql> insert into selectOrderdemo(Name,RankNumber) values('Larry',-100);
Query OK, 1 row affected (0.23 sec)
mysql> insert into selectOrderdemo(Name,RankNumber) values('John',50);
Query OK, 1 row affected (0.13 sec)
mysql> insert into selectOrderdemo(Name,RankNumber) values('Bob',0);
Query OK, 1 row affected (0.14 sec)
mysql> insert into selectOrderdemo(Name,RankNumber) values('Carol',-110);
Query OK, 1 row affected (0.23 sec)
mysql> insert into selectOrderdemo(Name,RankNumber) values('David',98);
Query OK, 1 row affected (0.21 sec
使用 select 语句显示表中的所有记录。查询如下 −
mysql> select *from selectOrderdemo;
这是输出 −
+----+-------+------------+ | Id | Name | RankNumber | +----+-------+------------+ | 1 | Larry | -100 | | 2 | John | 50 | | 3 | Bob | 0 | | 4 | Carol | -110 | | 5 | David | 98 | +----+-------+------------+ 5 rows in set (0.00 sec)
以下是选择 order by 的查询，其作用类似于数字。
案例 1 − 如果您希望结果按降序排列，则查询如下 −
mysql> select RankNumber FROM selectOrderdemo ORDER BY RankNumber+0 DESC;
这是输出 −
+------------+ | RankNumber | +------------+ | 98 | | 50 | | 0 | | -100 | | -110 | +------------+ 5 rows in set (0.00 sec)
案例 2 − 如果希望结果按升序排列，查询如下 −
mysql> select RankNumber FROM selectOrderdemo ORDER BY RankNumber+0;
这是输出 −
+------------+ | RankNumber | +------------+ | -110 | | -100 | | 0 | | 50 | | 98 | +------------+ 5 rows in set (0.00 sec)
案例 3 − 如果您想要所有列，请使用以下查询 −
mysql> select * FROM selectOrderdemo ORDER BY RankNumber+0 DESC;
这是输出 −
+----+-------+------------+ | Id | Name | RankNumber | +----+-------+------------+ | 5 | David | 98 | | 2 | John | 50 | | 3 | Bob | 0 | | 1 | Larry | -100 | | 4 | Carol | -110 | +----+-------+------------+ 5 rows in set (0.00 sec)
