在数据库中将字符串订购为数字？
要将字符串作为数字排序，请使用CAST()。以下是语法-
select *from yourTableName ORDER BY CAST(yourColumnName AS SIGNED) DESC;
让我们首先创建一个表-
mysql> create table DemoTable ( Id varchar(100) );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values('3');
mysql> insert into DemoTable values('20');
mysql> insert into DemoTable values('34');
mysql> insert into DemoTable values('21');
mysql> insert into DemoTable values('78');
mysql> insert into DemoTable values('90');使用select语句显示表中的所有记录-
mysql> select *from DemoTable;
这将产生以下输出-
+------+ | Id | +------+ | 3 | | 20 | | 34 | | 21 | | 78 | | 90 | +------+ 6 rows in set (0.00 sec)
以下是对整数排序的查询-
mysql> select *from DemoTable ORDER BY CAST(Id AS SIGNED) DESC;
这将产生以下输出-
+------+ | Id | +------+ | 90 | | 78 | | 34 | | 21 | | 20 | | 3 | +------+ 6 rows in set (0.02 sec)