如何在MySQL中仅命令一次返回重复的列值？
要在MySQL中仅返回一次列值，我们首先来看一个示例并创建一个表-
create table DemoTable680(Status varchar(100));
使用插入命令在表中插入一些记录-
insert into DemoTable680 values('Busy');
insert into DemoTable680 values('At Work');
insert into DemoTable680 values('Busy');
insert into DemoTable680 values('Blocked');
insert into DemoTable680 values('Offline');
insert into DemoTable680 values('Offline');
insert into DemoTable680 values('Blocked');使用select语句显示表中的所有记录-
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-
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)