C# SQL 表选择和计算不同的值

Question

i have ASP website with SQL database table. in this table column mane "type". i want to get all distinct values from this column with values count in datatable. for example for database table:

id  type
---------
1   type1
2   type2
3   type3
4   type2
5   type2
6   type3

i want to get the following datatable:

type  count
------------
type1   1
type2   3
type3   2

Answer 1

You can use

SELECT type, COUNT(type) as count
FROM Table1 
GROUP BY type

Result

|  type | count |
|-------|-------|
| type1 |     1 |
| type2 |     3 |
| type3 |     2 |

SqlFiddle DEMO

Answer 2

I would suggest that you do this in sql itself by using following query

SELECT type, COUNT(type) as count
FROM myTableName 
GROUP BY type

Answer 3

SQL

SELECT type, COUNT(type) as count
FROM Table1 
GROUP BY type

Linq

from t in <YourEntityObject>.YourTableName 
group t by t.type into myVar 
select new
   {
         k = myVar.Key,
         c = myVar.Count()
   };