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;
Related
I have a table tasks that looks like this:
userId caption status id
1 Paul done 1
2 Ali notDone 18
3 Kevin notDone 12
3 Elisa notDone 13
I join it with another table users to find the number of taskswhere status = notDone. I do it like this:
SELECT u.id,
t.number_of_tasks,
FROM users u
INNER JOIN (
SELECT userId, COUNT(*) number_of_tasks
FROM tasks
WHERE status = "notDone"
GROUP BY userId
) t ON u.id = t.userId
"""
Now, I want create another column captions that somehow includes a list of all captions that were included in the countand fulfil the join + where conditions.
For example, I would expect this as one of the rows. How can I achieve this?
userId number_of_tasks captions
3 2 ["Kevin", "Elisa"]
You can use json_group_array() aggregate function inside the subquery to create the list of captions for each user:
SELECT u.id, t.number_of_tasks, t.captions
FROM users u
INNER JOIN (
SELECT userId,
COUNT(*) number_of_tasks,
json_group_array(caption) captions
FROM tasks
WHERE status = 'notDone'
GROUP BY userId
) t ON u.id = t.userId;
I'm having the following request to get all artworks inner join with their user info:
SELECT a.*, row_to_json(u.*) as users
FROM artworks a INNER JOIN users u USING(address)
WHERE (a.flag != "ILLEGAL" OR a.flag IS NULL)
ORDER BY a.date DESC
LIMIT 100
How could i have the same query but including no more than 3 entries per user?
Each user have a unique id called "address"
I think DISTINCT ON only work for 1 per user, maybe ROW_NUMBER?
Thank you in advance, i'm pretty new to DB queries.
You need an extra column in which you specify the nth time that the user is in the table. This will look something like this:
USER | N
user1 | 1
user1 | 2
user1 | 3
user2 | 1
user2 | 2
Getting the extra column in a new table can be done by using the following code
--Create new Table as T
WITH T AS (
SELECT TOP 100
a.*,
row_to_json(u.*) as users,
ROW_NUMBER() OVER(PARTITION BY u.user ORDER BY a.date DESC) AS N
FROM artworks a INNER JOIN users u USING(address)
WHERE (a.flag != "ILLEGAL" OR a.flag IS NULL) )
--Select columns from your new table
SELECT columns from T
WHERE (T.N =1 OR T.N =2 OR T.N =3)
Just an addition to your original query will do. Count the resulting records for each user and then filter by the counter value.
I am using users.address as the user id.
SELECT * from
(
SELECT a.*, row_to_json(u.*) as userinfo,
row_number() over (partition by u.address order by a.date desc) as ucount
FROM artworks a INNER JOIN users u ON a.address = u.address
WHERE a.flag != "ILLEGAL" OR a.flag IS NULL
) t
WHERE ucount <= 3
ORDER BY date DESC
LIMIT 100;
A remark - you have users as a column alias and as a table name which may cause confusion. I have changed the alias to userinfo.
Tables
User
id
name
email
is_active
1
john
john#albert.com
FALSE
2
mike
mike#ss.com
TRUE
3
monica
monica#dunno.com
TRUE
4
joey
joey#as.com
FALSE
5
ross
ross#boss.com
FALSE
Subscriptions
id
house_id
plan name
status
1
1
A banana a month
inactive
2
2
An apple a month
active
3
3
A pear a month
active
House
id
name
1
John's House
2
Mike's House
3
Monica's House
4
Joey's House
5
Ross's House
House_Contact (legacy table)
id
house_id
is_primary
1
1
TRUE
2
2
FALSE
2
3
TRUE
House_User (new table)
id
house_id
is_owner
user_id
1
2
FALSE
2
2
4
FALSE
4
3
5
FALSE
5
Expected Results
The resulting table should include the following:
Does the user have a subscription regardless of status? If so, include, if not, disregard.
Get email & is_active from User table (if they have subscription)
Get is_primary OR is_owner (if they have a subscription)
Results should be distinct (no duplicate users)
house_id
email
is_owner
is_active
1
john#albert.com
TRUE
FALSE
2
mike#ss.com
FALSE
TRUE
3
monica#dunno.com
TRUE
TRUE
What I tried
SELECT
u.email AS "email",
u.is_active AS "is_active",
h.id AS "house_id",
is_owner
FROM
house c
INNER JOIN (
SELECT
house_id,
user_id
FROM
house_user) hu ON h.id = hu.house_id
INNER JOIN (
SELECT
id,
email,
is_active
FROM
USER) u ON hu.user_id = u.id
INNER JOIN (
SELECT
id,
email,
is_primary
FROM
house_contact) hc ON u.email = ch.email
INNER JOIN (
SELECT
house_id,
is_primary is_owner
FROM
house_contact
UNION
SELECT
house_id,
is_owner is_owner
FROM
house_user) t ON u.id = t.house_id)
ORDER BY
u.email
Results are half than if I remove the INNER JOIN with UNION statement. No idea how to proceed.
I'm particularly confused with unifying the column and the possible duplication.
My educated guess:
SELECT DISTINCT ON (u.id)
u.id, u.email, u.is_active, h.house_id, h.is_primary
FROM "user" u
LEFT JOIN (
SELECT hu.user_id, hu.house_id
, GREATEST(hc.is_primary, hu.is_owner) AS is_primary
FROM house_user hu
LEFT JOIN house_contact hc USING (house_id)
WHERE EXISTS (SELECT FROM subscription WHERE house_id = hu.house_id)
) h ON h.user_id = u.id
ORDER BY u.id, h.is_primary DESC NULLS LAST, h.house_id;
We don't need table house in the query at all.
I see three possible sources of conflict:
house_contact.is_primary vs. house_user.is_owner. Both seem to mean the same. The DB design is broken in this respect. Taking GREATEST() of both, which means true if either is true.
We don't care about subscription.status, so just make sure the house has at least one subscription of any kind with EXISTS, thereby avoiding possible duplicates a priori.
A user can live in multiple houses. We want only one row per user. So show the first house with is_primary (the one with the smallest house_id) if any. If there is no house, there is also no subscription. But the outer LEFT JOIN keeps the user in the result. Change to JOIN to skip users without subscription.
About DISTINCT ON:
Select first row in each GROUP BY group?
About sorting boolean values:
Sorting null values after all others, except special
Sort NULL values to the end of a table
You can use the joins as follows:
Select distinct hu.house_id, u.email, hu.is_owner, hc.is_primary
From user u join house_user hu on u.id = hu.user_id
Join subscriptions s on s.house_id = hu.house_id
Join house_contract hc on hc.house_id = s.house_id;
I have used distinct to remove duplicates if you have multiple data in the table for matching condition. You can remove it if not required in case it is not required.
From what I can tell, you want to start with a query like this:
select s.house_id, u.email, hu.is_owner, u.is_active
from subscriptions s left join
house_user hu
on s.house_id = hu.house_id left join
users u
on hu.user_id = u.id;
This does not return what you want, but it is rather unclear how your results are derived.
Given tables, Profiles, and Memberships where a profile has many memberships, how do I query profiles based on the number of memberships?
For example I want to get the number of profiles with 2 memberships. I can get the number of profiles for each membership with:
SELECT "memberships"."profile_id", COUNT("profiles"."id") AS "membership_count"
FROM "profiles"
INNER JOIN "memberships" on "profiles"."id" = "memberships"."profile_id"
GROUP BY "memberships"."profile_id"
That returns results like
profile_id | membership_count
_____________________________
1 2
2 5
3 2
...
But how do I group and sum the counts to get the query to return results like:
n | profiles_with_n_memberships
_____________________________
1 36
2 28
3 29
...
Or even just a query for a single value of n that would return
profiles_with_2_memberships
___________________________
28
I don't have your sample data, but I just recreated the scenario here with a single table : Demo
You could LEFT JOIN the counts with generate_series() and get zeroes for missing count of n memberships. If you don't want zeros, just use the second query.
Query1
WITH c
AS (
SELECT profile_id
,count(*) ct
FROM Table1
GROUP BY profile_id
)
,m
AS (
SELECT MAX(ct) AS max_ct
FROM c
)
SELECT n
,COUNT(c.profile_id)
FROM m
CROSS JOIN generate_series(1, m.max_ct) AS i(n)
LEFT JOIN c ON c.ct = i.n
GROUP BY n
ORDER BY n;
Query2
WITH c
AS (
SELECT profile_id
,count(*) ct
FROM Table1
GROUP BY profile_id
)
SELECT ct
,COUNT(*)
FROM c
GROUP BY ct
ORDER BY ct;
I'm trying to get 3 random unique profiles with the same sex ID as the current user ID (orig.id_user = 6 in this example), and their respective reviews.
SELECT DISTINCT u.id_user, s.review
FROM user AS u
CROSS JOIN user AS orig ON orig.id_sex = u.id_sex
INNER JOIN user_review AS s ON s.id_user_to = u.id_user
WHERE orig.id_user = 6
ORDER BY RAND()
LIMIT 3
Somehow, the id_user column displays repeated values. Why?
UPDATE (assuming i have the id_sex value)
SELECT DISTINCT s.id_user_to, s.id_user_from, s.review
FROM user_review AS s
LEFT JOIN user AS u ON u.id_user = s.id_user_to
WHERE u.id_sex = 2
ORDER BY RAND()
LIMIT 20
But this is still returning repeated rows in the id_user_to column, they should be unique values because of the DISTINCT.
SOLUTION using GROUP BY
SELECT us.id_user_to, us.review
FROM user_review AS us
LEFT JOIN user AS u ON u.id_user = us.id_user_to
WHERE u.id_sex = 2
GROUP BY us.id_user_to
ORDER BY RAND()
LIMIT 3