SQL select query using group by - mysql

Question

How to get the TeamCount and TeamLead Name currectly
Teams | TeamCount | TeamLead Name
-------------------------------------
| Team1 | 2 | NULL
| Team2 | 2 | NULL
| Team1 | 1 | Prashanth
Some times Team may or may not have the team lead.
So we just have to show the TeamLead name as null,
if team lead is not found for the team
I need some help to get the out as below
Teams | TeamCount | TeamLead Name
---------------------------------
Team1 | 3 | Prashanth
Team2 | 2 | NULL

Answer 1

Here you are:
MySQL:
select team as teamId, sum(teamcount) as teamcount,
(select teamleadname from teams
where teamId = teams.team and teamleadname is not null
limit 1) as teamleadname
from teams
group by team
http://sqlfiddle.com/#!9/5889d/39
SQl Server:
declare #teams TABLE(Team varchar(20), TeamCount int, TeamLeadName varchar(20));
INSERT INTO #teams
VALUES
('Team1', 2, null),
('Team2', 2, null),
('Team1', 1, 'Prashanth')
select l.Team, l.TeamCount, r.TeamLeadName
from
(select Team , sum(TeamCount) as TeamCount from #teams group by Team) as l
left outer join
(select Team, TeamLeadName
from
(select Team, TeamLeadName, row_number() over(partition by Team order by TeamLeadName desc) as roworder
from #teams) as o where o.roworder = 1
) as r
on l.Team = r.Team
Hope this help.

Answer 2

...and here you go!
create table test2 as
select distinct c.teams,sum(c.TeamCount) as SUM,c.TeamName
from
(select a.Teams,a.TeamCount,b.TeamName from team as a
left outer join
(select * from team where TeamName ne "") as b
on a.Teams = B.Teams) as c
group by c.Teams;
You should try to develop these solutions by working from the inside out and build the query in steps

Answer 3

You can do this with a LEFT OUTER join between Team and TeamMembers, and including the IsLead into the join criterion, before grouping by the Team name - this will exclude non-leads:
SELECT T.Name, MIN(TM.TName) AS Lead
FROM Teams T
LEFT OUTER JOIN TeamMembers TM
ON TM.TeamId = T.Id AND TM.IsLead = 1
GROUP BY T.Name;
SqlFiddle here
The TeamCount doesn't seem to make sense here - if you can elaborate on how you intend deriving it, perhaps we can help here
PS : You've tagged both MySql and Oracle - don't do this please.