在字段中获取所有元素数的 MySQL 查询?


为此,可以使用 COUNT() 方法。我们首先创建一个表 -

mysql> create table DemoTable
-> (
-> ProductName varchar(100)
-> );
Query OK, 0 rows affected (0.59 sec)

使用 insert 命令在表中插入一些记录 -

mysql> insert into DemoTable values('Product-1');
Query OK, 1 row affected (0.26 sec)

mysql> insert into DemoTable values('Product-2');
Query OK, 1 row affected (0.12 sec)

mysql> insert into DemoTable values('Product-3');
Query OK, 1 row affected (0.16 sec)

mysql> insert into DemoTable values('Product-3');
Query OK, 1 row affected (0.29 sec)

mysql> insert into DemoTable values('Product-2');
Query OK, 1 row affected (0.15 sec)

mysql> insert into DemoTable values('Product-4');
Query OK, 1 row affected (0.12 sec)

mysql> insert into DemoTable values('Product-5');
Query OK, 1 row affected (0.14 sec)

mysql> insert into DemoTable values('Product-1');
Query OK, 1 row affected (0.11 sec)

使用 select 语句从表中显示所有记录 -

mysql> select *from DemoTable;

输出

这将生成以下输出 -

+-------------+
| ProductName |
+-------------+
| Product-1   |
| Product-2   |
| Product-3   |
| Product-3   |
| Product-2   |
| Product-4   |
| Product-5   |
| Product-1   |
+-------------+
8 rows in set (0.00 sec)

以下查询用于获取字段中所有元素的计数 -

mysql> select ProductName,count(ProductName) as TotalCount from DemoTable group by ProductName;

输出

这将生成以下输出 -

+-------------+------------+
| ProductName | TotalCount |
+-------------+------------+
| Product-1   | 2          |
| Product-2   | 2          |
| Product-3   | 2          |
| Product-4   | 1          |
| Product-5   | 1          |
+-------------+------------+
5 rows in set (0.05 sec)

更新于:30-06-2020

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