如何使用group by data进行sql查询

Question

我的表格如下所示：

     id        name     
---|------|------------|
   |   1  | IP2.0-v1.0 |
   |   2  | IP2.0-v2.0 |
   |   3  | IP1.0-v1.0 |
   |   4  | IP1.1-v1.0 |

我想按结果分组如下：

     name        count     
---|----------|------------|
   |   IP2.0  |     2      |
   |   IP1.0  |     1      |
   |   IP1.1  |     1      |

如何使用group by？

设法获取SQL查询

  

从table_a GROUP BY ...........

中选择名称，计数（*）

Answer 1

您希望子查询在

组之前执行子字符串

select nameSub, count(*) from
(select id, substring(name,1,5) as nameSub from table)
group by nameSub

Answer 2

SELECT SUBSTRING (NAME,1,5), COUNT(*) FROM table_a GROUP BY SUBSTRING (NAME,1,5)

Answer 3

MySQL Fiddle和SQL Server Fiddle：

SELECT LEFT(name, 5), count(*) 
FROM MyTable
GROUP BY LEFT(name, 5)

Answer 4

试试这个：

SELECT   SUBSTRING(Name,1,CHARINDEX('-',Name)-1) AS Name, COUNT(*) AS Count
FROM     table_a
GROUP BY SUBSTRING(Name,1,CHARINDEX('-',Name)-1)

如果SUBSTRING的长度变化

，则

Name非常有用

Answer 5

尝试使用SUBSTRING( str FROM pos FOR len )

SELECT 
    SUBSTRING(`name` from 1 for 5) as name_res, 
    COUNT(*) 
FROM @TABLE
GROUP BY name_res;