I am building a chat site and for presenting the chats to the audiences, I have 3 Dropdownlists - Sports (Default is All Sports), Day/Month/Year, Users online/Total Users.
Now, if by default all sports is selected and I pick 1 month and Total users, the expected result should be
My query is
SELECT DISTINCT roo.[Sports],
roo.[Name],
COUNT(DISTINCT chu.ChatUserLogId) AS TotalUsers,
COUNT(DISTINCT liu.[LoggedInUserID]) AS UserOnline
FROM Room AS roo
LEFT JOIN LoggedInUser AS liu ON roo.RoomID = liu.RoomID
LEFT JOIN ChatUserLog AS chu ON roo.RoomID = chu.RoomID
AND chu.LoggedInTime >= DATEADD(DAY,-30,GETDATE())
GROUP BY roo.[Sports], roo.[Name]
ORDER BY TotalUsers DESC
One person suggested that with my method I am actually multiplying the row because of the two joins & so I need to aggregate first, then join.
So in the end, I tried this query too
with agg_ChatUserLog as (select RoomId, count(*) as cnt_user_tot from ChatUserLog WHERE LoggedInTime >= DATEADD(DAY,-30,GETDATE()) group by RoomId),
agg_LoggedInUser as (select RoomId, count(*) as cnt_user_logged from LoggedInUser group by RoomId)
select Sports, Name, cnt_user_tot, cnt_user_logged from Room r
left outer join agg_ChatUserLog acu on acu.RoomId = r.RoomId
left outer join agg_LoggedInUser alu on alu.RoomId = r.RoomId;
But this is also multiplying the results.
Where am I making the mistake in both the query? Thanks in advance and have a nice day ahead.
SAMPLE DATA IS:
Chatroom name Total Users Online users
Basketball
Roomname27 32 5
Roomname11 15 3
Roomname32 8 1
Football
Roomname5 63 12
Roomname18 44 7
Roomname4 15 2
you can try another syntax :
select Sports,
Name,
coalesce(
(
select count(distinct C.ChatUserLogId)
from ChatUserLog as C
where C.RoomId = R.RoomId
and C.LoggedInTime >= DATEADD(DAY,-30,GETDATE())
),
0) AS TotalUsers,
coalesce(
(
select count(distinct D.LoggedInUserID)
from LoggedInUser as D
where D.RoomId = R.RoomId
),
0) AS UserOnline
from Room R
with this syntax, you will never have more results than number of roomname.
but you also have room whitout audience
Related
I have 3 tables
User Table
id
Name
1
Mike
2
Sam
Score Table
id
UserId
CourseId
Score
1
1
1
5
2
1
1
10
3
1
2
5
Course Table
id
Name
1
Course 1
2
Course 2
What I'm trying to return is rows for each user to display user id and user name along with the sum of the maximum score per course for that user
In the example tables the output I'd like to see is
Result
User_Id
User_Name
Total_Score
1
Mike
15
2
Sam
0
The SQL I've tried so far is:
select TOP(3) u.Id as User_Id, u.UserName as User_Name, SUM(maxScores) as Total_Score
from Users as u,
(select MAX(s.Score) as maxScores
from Scores as s
inner join Courses as c
on s.CourseId = c.Id
group by s.UserId, c.Id
) x
group by u.Id, u.UserName
I want to use a having clause to link the Users to Scores after the group by in the sub query but I get a exception saying:
The multi-part identifier "u.Id" could not be bound
It works if I hard code a user id in the having clause I want to add but it needs to be dynamic and I'm stuck on how to do this
What would be the correct way to structure the query?
You were close, you just needed to return s.UserId from the sub-query and correctly join the sub-query to your Users table (I've joined in reverse order to you because to me its more logical to start with the base data and then join on more details as required). Taking note of the scope of aliases i.e. aliases inside your sub-query are not available in your outer query.
select u.Id as [User_Id], u.UserName as [User_Name]
, sum(maxScore) as Total_Score
from (
select s.UserId, max(s.Score) as maxScore
from Scores as s
inner join Courses as c on s.CourseId = c.Id
group by s.UserId, c.Id
) as x
inner join Users as u on u.Id = x.UserId
group by u.Id, u.UserName;
Question: Show the names of all players who have the following:
the difference between the minimum and maximum number of games
this players is greater than 5.
select p.name
from player p
join competition c
on c.playerID = p.playerID
where (
(select count(*) from competition
where count(games) > 1
group by playerID
) - (
select count(*) from competition
where count(games) <= 1
group by playerID
))> 5;
I'm kind of lost. I'm not so sure is this the right way, how I should proceed: should I use count and find the minimum and maximum number of games and compare with greater than 5 or should I use instead of count, min and max functions. Would be very grateful, if someone can explain me the logic of this.
Tables:
player competition
------- --------
playerID playerID
name games
birthday date
address
telefon
SELECT
P.Name,
MIN(C.Games) MinGame,
MAX(C.Games) MaxGame,
FROM Player P
INNER JOIN Competition C
ON C.PlayerId = P.PlayerId
GROUP BY P.Id, P.Name
HAVING MAX(C.Games) - MIN(C.Games) > 5
It should be a simple query:
With tab1 AS (Select player.name, min(games) mx_game, max(games) min_game,
max(games) - min(games) diff
from player JOIN competition ON player.player_id = competition.id
group by player.player_id, player.name)
Select tab1.name from tab1
WHERE diff >5;
I am adding player_id in the group by as player_name could be similar for 2 person.
How to find the user with the most referrals that have at least three blue shoes using PostgreSQL?
table 1 - users
name (matches shoes.owner_name)
referred_by (foreign keyed to users.name)
table 2 - shoes
owner_name (matches persons.name)
shoe_name
shoe_color
What I have so far is separate queries returning parts of what I want above:
(SELECT count(*) as shoe_count
FROM shoes
GROUP BY owner_name
WHERE shoe_color = “blue”
AND shoe_count>3) most_shoes
INNER JOIN
(SELECT count(*) as referral_count
FROM users
GROUP BY referred_by
) most_referrals
ORDER BY referral_count DESC
LIMIT 1
Two subqueries seem like the way to go. They would look like:
SELECT s.owner_name, s.show_count, r.referral_count
FROM (SELECT owner_name, count(*) as shoe_count
FROM shoes
WHERE shoe_color = 'blue'
GROUP BY owner_name
HAVING shoe_count >= 3
) s JOIN
(SELECT referred_by, count(*) as referral_count
FROM users
GROUP BY referred_by
) r
ON s.owner_name = r.referred_by
ORDER BY r.referral_count DESC
LIMIT 1 ;
I have a table called BB_BOATBKG which holds passengers travel details with columns Z_ID, BK_KEY and PAXSUM where:
Z_ID = BookingNumber* LegNumber
BK_KEY = BookingNumber
PAXSUM = Total number passengers travelled in each leg for a particular booking
For Example:
Z_ID BK_KEY PAXSUM
001234*01 001234 2
001234*02 001234 3
001287*01 001287 5
001287*02 001287 5
002323*01 002323 7
002323*02 002323 6
I would like to get a list of all Booking Numbers BK_KEY from BB_BOATBKG where the total number of passengers PAXSUM is different in each leg for the same booking
Example, For Booking number A, A*Leg01 might have 2 Passengers, A* Leg02 might have 3 passengers
Dependent of your RDBMs there might be several options availible. A solution that should work for most is:
SELECT A.Z_ID, A.BK_KEY, A.PAXSUM
FROM BB_BOATBKG A
JOIN (
SELECT BK_KEY
FBB_BOATBKGROM BB_BBK_KEY
GROUP BY BK_KEY
HAVING COUNT( DISTINCT PAXSUM ) > 1
) B
ON A.BK_KEY = B.BK_KEY
If your DBMS support OLAP functions, have a look at RANK() OVER (...)
It's a little counterintuitive, but you could join the table to itself on {BK_KEY, PAXSUM} and pull out only the records whose joined result is null.
I think this does it:
SELECT
a.BK_KEY
FROM
BB_BOATBKG a
LEFT OUTER JOIN BB_BOATBKG b ON a.BK_KEY = b.BK_KEY AND a.PAXSUM = b.PAXSUM
WHERE
b.Z_ID IS NULL
GROUP BY
a.BK_KEY
Edit: I think I missed anything beyond the trivial case. I think you can do it with some really nasty subselecting though, a la:
SELECT
b.BK_KEY
FROM
(
SELECT
a.BK_KEY,
Count = COUNT(*)
FROM
(
SELECT
a.BK_KEY,
a.PAXSUM
FROM
BB_BOATBKG a
GROUP BY
a.BK_KEY,
a.PAXSUM
HAVING
COUNT(*) = 1
) a
GROUP BY
a.BK_KEY
) b
INNER JOIN
(
SELECT
c.BK_KEY,
Count = COUNT(*)
FROM
BB_BOATBKG c
GROUP BY
c.BK_KEY
) c ON b.BK_KEY = c.BK_KEY AND b.Count = c.Count
Here is the schema for the database: http://i.stack.imgur.com/omX60.png
Question is: How many people have at least five еntitlements?
I've got this, please tell me how wrong it is and fix it.
select count(personId)
from serialNumber_tbl natural join entitlement_tbl
group by personId
having sum(entitlementID) > 5
Thank you.
The condition for at least 5 is >= 5, not > 5
You need to count the distinct ids in the entitlement table, not person
This gives you the persons, next you need to subquery it to find the count of persons.
select count(personId)
FROM
(
select personId
from serialNumber_tbl natural join entitlement_tbl
group by personId
having count(distinct entitlement_id) >= 5
) X
Your request isn't exactly clear. Are you asking for the count of people with more than five entitlement rows whether they exist on multiple serial numbers or not? If so, you could do something like:
Select Count(*) As CountOfPeople
From Person_tbl As P
Where Exists (
Select 1
From serialNumbers As S1
Join entitlement_tbl As E1
On E1.serialNumberId = S.serialNumberId
Where S1.personId = P.personId
Having Count(*) >= 5
)
Or is it that you are asking to find the number of people that have a serialNumber with more than five entitlements? If that is the case, then you could do something like:
Select Count(*) As CountOfPeople
From Person_tbl As P
Where Exists (
Select 1
From serialNumbers As S1
Join entitlement_tbl As E1
On E1.serialNumberId = S.serialNumberId
Where S1.personId = P.personId
Having Count( Distinct S1.serialNumberId ) >= 5
)