使用MySQL GROUP BY从特定公司获取员工姓名？

让我们首先创建一个表-

mysql> create table DemoTable642(
   EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY,EmployeeName archar(100), EmployeeCompanyNamevarchar(100)
);

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable642(EmployeeName,EmployeeCompanyName) values('John','Google');
mysql> insert into DemoTable642(EmployeeName,EmployeeCompanyName) values('Carol','Microsoft');
mysql> insert into DemoTable642(EmployeeName,EmployeeCompanyName) values('John','Amazon');
mysql> insert into DemoTable642(EmployeeName,EmployeeCompanyName) values('Carol','Google');
mysql> insert into DemoTable642(EmployeeName,EmployeeCompanyName) values('John','Flipkart');

使用select语句显示表中的所有记录-

mysql> select *from DemoTable642;

这将产生以下输出-

+------------+--------------+---------------------+
| EmployeeId | EmployeeName | EmployeeCompanyName |
+------------+--------------+---------------------+
| 1          | John         | Google              |
| 2          | Carol        | Microsoft           |
| 3          | John         | Amazon              |
| 4          | Carol        | Google              |
| 5          | John         | Flipkart            |
+------------+--------------+---------------------+
5 rows in set (0.00 sec)

以下是从特定公司获取员工姓名的查询-

mysql> select EmployeeName from DemoTable642
   where EmployeeCompanyName="Google"
   group by EmployeeName;

这将产生以下输出-

+--------------+
| EmployeeName |
+--------------+
| John         |
| Carol        |
+--------------+
2 rows in set (0.00 sec)