MySQL 从 5 个相似值中仅选择一个值?
mysqlmysqli database
首先我们创建一个表 −
mysql> create table DemoTable800 ( Value int ); Query OK, 0 rows affected (0.59 sec)
使用 insert 命令在表中插入一些记录。Here, we have inserted 5 similar values −
mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable800 values(10); Query OK, 1 row affected (0.10 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable800;
这将产生以下输出 -
+-------+ | Value | +-------+ | 10 | | 10 | | 10 | | 10 | | 10 | +-------+ 5 rows in set (0.00 sec)
以下查询从 5 个相似值中仅选择一个值 −
mysql> select distinct Value from DemoTable800
这将产生以下输出 -
+-------+ | Value | +-------+ | 10 | +-------+ 1 row in set (0.00 sec)
