如何计算已经执行的SQL查询的不同结果？

Question

    select application from l3_usage 
where function in ('dbms', 'web', 'app') 
group by application, function 
order by application 

This is the result image when I execute the above query.

I want to now count the number of times applications occur. So for example: Budget : 3 CSR : 3 FMS : 3 Facilities : 1 Inventory : 3

etc...

I have tried

   select application, count(application) from l3_usage 
where function in ('dbms', 'web', 'app') 
group by application 
order by application 

but I get random count numbers that do not relate to the count I was looking for.

Could anyone help? Thanks!

EDIT :::::

my ultimate purpose of doing this is to get only applications that have count values less than 3.

Which in this case, should return just "Facilities" and "SCM".

Answer 1

Try this query:

SELECT x.application, COUNT(*) As Frequency
FROM
(
    SELECT application
    FROM l3_usage
    WHERE function IN ('dbms', 'web', 'app') 
    GROUP BY application, function 
    ORDER BY application
) AS x
GROUP BY x.application
HAVING COUNT(*) < 3
ORDER BY COUNT(*)

I query the result set you posted in your answer and obtain the COUNT for each group. Notice that this COUNT is the number of unique function values for each application group. You should get this result:

+-------------+-----------+
| application | Frequency |
+-------------+-----------+
| Facilities  |     1     |
| SCM         |     1     |
+-------------+-----------+

Update:

A much easier way to do your query is:

SELECT application, COUNT(DISTINCT function) As Frequency
FROM l3_usage
WHERE function IN ('dbms', 'web', 'app') 
GROUP BY application
HAVING COUNT(DISTINCT function) < 3
ORDER BY application

You had the right idea in the beginning, but you needed to SELECT the number of distinct function s for each application group.

Answer 2

SELECT application,COUNT(CASE
               WHEN application IS NOT NULL THEN 1
             END)
FROM   table group by application

I found reference from here

Edit

---

select * from(
SELECT typing,COUNT(CASE
               WHEN typing IS NOT NULL THEN 1
             END) as counts
FROM   ss  group by typing ) abc where counts<3

Answer 3

I have used subqueries which I had concatenated count to your query. If you want distinct row count use distinct in-front of count(*) in @count query

declare @count nvarchar(max)= (select count(*) 
                               from l3_usage 
                               where function in ('dbms', 'web', 'app'))

declare @sql nvarchar(max) = 'select a,count(*),'+@count+' as count  from l3_usage 
where function in (''dbms'', ''web'', ''app'') '

exec(@sql)