MySQL 如何从varchar列中获取大于特定值的值

由于要获取大于特定值的值的列是VARCHAR，请使用CAST（）函数。例如，要从具有varchar值的列中提取大于999的值。

让我们首先创建一个表-

mysql> create table DemoTable
(
   Value varchar(100)
);
Query OK, 0 rows affected (1.02 sec)

使用insert命令在表中插入一些记录-

mysql> insert into DemoTable values('900');
Query OK, 1 row affected (0.49 sec)
mysql> insert into DemoTable values('1090');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('860');
Query OK, 1 row affected (0.25 sec)
mysql> insert into DemoTable values('12345');
Query OK, 1 row affected (0.30 sec)
mysql> insert into DemoTable values('908345');
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 DemoTable;

这将产生以下输出-

+--------+
| Value  |
+--------+
| 900    |
| 1090   |
| 860    |
| 12345  |
| 908345 |
+--------+
5 行记录 (0.00 秒)

以下是从varchar列中获取大于特定值的值的查询-

mysql> select max(cast(Value AS SIGNED)) from DemoTable;

这将产生以下输出-

+----------------------------+
| max(cast(Value AS SIGNED)) |
+----------------------------+
|                     908345 |
+----------------------------+
1 行记录 (0.05 秒)

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