MySQL 如何订购返回重复列值只出现一次

要在MySQL中仅返回一次列值，请首先看一个示例并创建一个表 –

mysql> create table DemoTable680(Status varchar(100));
Query OK, 0 rows affected (0.75 sec)

使用插入命令在表中插入一些记录 –

mysql> insert into DemoTable680 values('Busy');
Query OK, 1 row affected (0.36 sec)
mysql> insert into DemoTable680 values('At Work');
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable680 values('Busy');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable680 values('Blocked');
Query OK, 1 row affected (0.28 sec)
mysql> insert into DemoTable680 values('Offline');
Query OK, 1 row affected (0.67 sec)
mysql> insert into DemoTable680 values('Offline');
Query OK, 1 row affected (0.23 sec)
mysql> insert into DemoTable680 values('Blocked');
Query OK, 1 row affected (0.14 sec)

使用select语句显示表中的所有记录 –

mysql> select *from DemoTable680;

这将产生以下输出 –

+---------+
| Status  |
+---------+
| Busy    |
| At Work |
| Busy    |
| Blocked |
| Offline |
| Offline |
| Blocked |
+---------+
7 rows in set (0.00 sec)

以下是在MySQL中仅返回重复列值一次的查询 –

mysql> select distinct Status from DemoTable680 order by Status;

这将产生以下输出 –

+---------+
| Status  |
+---------+
| At Work |
| Blocked |
| Busy    |
| Offline |
+---------+
4 rows in set (0.00 sec)

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