如何使用分组数据进行SQL查询

Question

I have a table which look like below:

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

I would like to have group by result such as below:

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

How can I manage to get SQL query using group by?

Select name,count(*) from table_a GROUP BY ...........

Answer 1

You want a subquery to do the substring before the group by

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 and SQL Server Fiddle :

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

Answer 4

Try this:

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

SUBSTRING is useful if the length of Name vary

Answer 5

Try with SUBSTRING( str FROM pos FOR len )

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