如何在 MySQL 中命令仅返回一次重复的列值?
mysqlmysqli database更新于 2025/10/21 13:00:17
要在 MySQL 中仅返回一次列值，让我们首先看一个例子并创建一个表 −
mysql> create table DemoTable680(Status varchar(100)); Query OK, 0 rows affected (0.75 sec)
使用 insert 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 中仅返回一次重复列值的查询 -
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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mysql 参考教程 - 该教程包含有关 mysql 的更多信息:https://www.cainiaomax.com/mysql/
