English | 简体中文 | 繁體中文 | Русский язык | Français | Español | Português | Deutsch | 日本語 | 한국어 | Italiano | بالعربية
让我们来看一个获取列中每个不同值的计数的示例。首先,我们将创建一个表。
命令 CREATE 用于创建表。
mysql> create table DistinctDemo1 - > ( - > id int, - > name varchar(100) - > );
mysql> insert into DistinctDemo1 values(1,'John'); mysql> insert into DistinctDemo1 values(2,'John'); mysql> insert into DistinctDemo1 values(3,'John'); mysql> insert into DistinctDemo1 values(4,'Carol'); mysql> insert into DistinctDemo1 values(5,'David');
mysql> select * from DistinctDemo1;
هذا هو الناتج لعرض جميع السجلات.
+------+-------+ | id | name | +------+-------+ | 1 | John | | 2 | John | | 3 | John | | 4 | Carol | | 5 | David | +------+-------+ 5 rows in set (0.00 sec)
هناك بناء الجملة للحصول على العدد.
mysql> SELECT name, COUNT(1) as OccurenceValue FROM DistinctDemo1 GROUP BY name ORDER BY OccurenceValue;
هذا هو الناتج.
+-------+----------------+ | name | OccurenceValue | +-------+----------------+ | Carol | 1 | | David | 1 | | John | 3 | +-------+----------------+ 3 rows in set (0.04 sec)