Is it necessary to nest a double COUNT here? - mysql

So, I have three tables for a service that sells tickets for events:
Event(id)
Ticket(id, venue_id, seller_id)
Venue(id, event_id)
Seller(id)
And I would like to detect, for every event that I have, how many sellers (of type 1) there are that have only only ticket for sale (and for that ticket to be of the corresponding event). Like
Event_id; First_time_sellers
2814;3
3092;24
124;1
...
I have attempted this with two queries, both failing getting wrong results
SELECT event_id,
COUNT(DISTINCT rookie_seller)
FROM
(SELECT event_id,
rookie_seller,
tickets
FROM
(SELECT DISTINCT event.id AS event_id,
seller.id AS rookie_seller,
COUNT(DISTINCT ticket.id) AS tickets
FROM ticket
JOIN venue ON ticket.venue_id = venue.id
JOIN event ON venue.event_id = event.id
JOIN seller ON ticket.seller_id = seller.id
WHERE seller.type = 1
AND ticket.isforsale = 1
GROUP BY rookie_seller) a
WHERE tickets = 1) b
GROUP BY event_id
and
SELECT event.id,
a.seller_id,
a.tickets
FROM ticket
JOIN (
SELECT seller.id AS seller_id,
COUNT(DISTINCT ticket.id) AS tickets
FROM ticket
JOIN seller ON ticket.seller_id = seller.id
WHERE seller.type = 1
AND ticket.isforsale = 1
GROUP BY seller_id) a ON ticket.seller_id = a.seller_id
JOIN venue ON ticket.venue_id = venue.id
JOIN event ON venue.event_id = event.id
WHERE a.tickets = 1
I am really not sure what the problem is. the joins should be fine, and the conditions on the count as well, right?
Thanks for any piece of advice :)

You do need a subquery for this. But you can do it more simply:
SELECT event_id, COUNT(*)
FROM (SELECT s.id, v.event_id, COUNT(*) as numTickets
FROM ticket t JOIN
seller s
ON t.seller_id = s.id JOIN
venue v
ON t.venue_id = v.id
WHERE s.type = 1 AND t.isforsale = 1
GROUP BY s.id
HAVING COUNT(*) = 1
) s
GROUP BY event_id;

Related

I need to get specific ids from db if these are in current and last quarter using SQL

[DB Table]
SELECT b.first_name, b.last_name, a.pod_name, a.category, c.user_id,
SUM(IF(QUARTER(CURDATE())-1 OR (QUARTER(CURDATE())-2) AND a.user_id, 1, 0)) AS flag FROM kudos a
INNER JOIN users b ON a.user_id = b.id INNER JOIN users_groups c ON a.user_id = c.user_id
INNER JOIN groups d ON c.group_id = d.id WHERE a.group_name = 'G2' AND d.id IN (7,8,9,11,12,13,14,15,16,17,21,22,23,24,25,26,27,28)
AND QUARTER(CURDATE())-1 = a.quarter ORDER BY a.final_score+0 DESC
I need to get the user_ids of those users which are both in quarter 1 and 2 from table.
Tried above query but failed to get expected results.
Can someone please guide me on this?
if you only need user_id then you can do this :
select user_id
from tablename
where quarter in (1,2)
group by user_id
having count(distinct quarter) = 2
another way is to use window function, assuming you have one user id in each quarter:
select * from (
select * , count(*) over (partition by user_id) cn
from tablename
where quarter in (1,2)
) t where cn = 2

Showing maximum

I want to show maximum of guarantee which specific user has. For example user has bought 3 items which have 1,2,5 years guarantee. So I want to show 5 years guarantee and name of this product.
I did subquery in case few products have this same guarantee.
SELECT t.`id-user`, name, guarantee FROM transactions t
JOIN user u ON `t`.`id-user` = `u`.`id-user`
JOIN products p ON `p`.`id-product = `t`.`id-product`
WHERE guarantee = (SELECT MAX(p2.guarantee)
FROM products p2
WHERE `p2`.`id-product` = `p`.`id-product`)
This query shows all products and their guarantees.
I think the simplest method is the substring_index()/group_concat() method for getting values associated with a maximum/minimum:
SELECT t.iduser, u.name,
MAX(p.guarantee) as guarantee,
SUBSTRING_INDEX(GROUP_CONCAT(p.name ORDER BY p.guarantee DESC), ',', 1)
FROM transactions t JOIN
user u
ON t.iduser = u.iduser JOIN
products p
ON p.idproduct = t.idproduct
GROUP BY t.iduser, u.name;
You can use your method too, but the correlated subquery is tricky:
SELECT t.iduser, u.name, p.guarantee, p.name
FROM transactions t JOIN
user u
ON t.iduser = u.iduser JOIN
products p
ON p.idproduct = t.idproduct
WHERE p.guarantee = (SELECT MAX(p2.guarantee)
FROM transactions t2 JOIN
products p2
ON p2.idproduct = t2.idproduct
WHERE t2.iduser = u.iduser
);
I think it work.
select [User].Name as [UserName],
Product.MaxGuarantee,
Product.Name as Product_Name
from [Users] [User]
left join Transactions [Transaction]
on [Transaction].[User] = [User].ID
cross apply(
select max(guarantee) MaxGuarantee, Name
from Products
where ID = [Transaction].Product
) Product
where [User].ID = ''

MYSQL Count where active across tables

I have three tables:
person
-----------
person_id, active
person_team
-----------
person_id, team_id, active
team
-----------
team_id, active
I'd like to get the count on teams from each person where active is true in each table.
So far I have:
SELECT t.id, t.title, t.created_timestamp, COUNT(p_t.tag_id) AS count
FROM team t
LEFT JOIN
person_team p_t ON p_t.team_id = t.id AND p_t.active = 1
WHERE
t.active = 1
GROUP BY t.id
ORDER BY t.title
This gets the count where team and person - team are active, but doesn't take into account whether person is active. Should I use a sub query or another type of join?
You need to add the person table in a join, and count a column from that table:
SELECT t.id, t.title, t.created_timestamp, COUNT(p.id) AS count
FROM team t
LEFT JOIN
person_team p_t ON p_t.team_id = t.id AND p_t.active = 1
LEFT JOIN
person p ON p_t.person_id = p.id AND p.active = 1
WHERE
t.active = 1
GROUP BY t.id
ORDER BY t.title
You should use a inner join on sub select for get the columns not in group by
select k.id, t.title, t.created_timestamp, k.count from
( SELECT t.id COUNT(p_t.tag_id) AS count
FROM team t
LEFT JOIN
person_team p_t ON p_t.team_id = t.id AND p_t.active = 1
WHERE
t.active = 1
GROUP BY t.id ) k
inner join team t on t.id = k.id

Select Row for Max Sum Value In Multiple Tables MYSQL

I need to query for the users with highest amount of sales by all projects, where the users are in users table, sales in units table, projects in projects table.
Projects Top Agent Total Sales for Project
Project A User A 100000
Project B User B 20000
Project C User A 1000
Project D - 0
The Projects column is list all the projects regardless it has sales or not.
The Top Agent column is list the user with the highest sales in the project.
The Total Sales for Project is the total sales for a projects.
The agent column i got is incorrect because there is someone else has the highest sales, the query seems to return the first row of the result
SELECT projects, pid, CASE WHEN agent is null THEN '-' ELSE agent END as agent,
CASE WHEN FORMAT(topagent,0) > 0 THEN FORMAT(topagent,0) ELSE 0 END as salesvolume
FROM (
SELECT projects.name as projects, projects.id as pid,
concat(users.f_name, ' ', users.l_name) as agent,
SUM(units.price) AS topagent
FROM users inner join bookings on bookings.agent_id = users.id
inner join units on bookings.unit = units.id
inner join types on types.id = units.types_id
inner join projects on projects.id = types.project_id
WHERE units.status = 'Sold'
GROUP BY pid
union
select projects.name as projects, projects.id as pid,
concat(users.f_name, ' ', users.l_name) as agent,
SUM(units.price) AS topagent
from projects left outer join types on projects.id = types.project_id
left outer join units on types.id = units.types_id and units.status = 'Sold'
left outer join bookings on units.id = bookings.unit and units.status = 'Sold'
left outer join users on bookings.agent_id = users.id and units.status = 'Sold'
group by pid
) a
GROUP BY pid
order by topagent desc
Try it if helps you-
SELECT a.prjname, IFNULL(usr.name,'-') AS Top_Agent, SUM(a.sale) AS Total_Sales_for_Project
FROM
(
SELECT prj.id AS prjid,prj.name AS prjname,usr.id,usr.name AS usrname,IFNULL(SUM(unit.price),0) AS sale
FROM projects AS prj
LEFT JOIN `types` AS typ ON typ.project_id=prj.id
LEFT JOIN units AS unt ON unt.type_id=typ.id AND unt.status='sold'
LEFT JOIN bookings bkg ON bkg.unit=unt.id
LEFT JOIN users usr ON usr.id=bkg.agent_it
GROUP BY prj.id,usr.id
ORDER BY prj.id,usr.id,sale DESC
) a
GROUP BY a.prjid
Your column aliases are confusing to read. In English, it seems what you mean by topagent is "sum of sales by a human". But in SQL, your GROUP BY pid means that the SUM(units.price) really means "sum of sales in a project".
Then the UNION adds a list of projects to a list of users. The agent names are basically random at this point.
If I decipher the requirements as "a list of projects ranked by the sales values of each project's top sales agent", then you'd have SQL as below:
SELECT
pid,
projects.name as project_name,
IFNULL(a.top_agent_name,'-') as top_agent_name,
CASE WHEN FORMAT(top_agent_sales,0) > 0 THEN FORMAT(top_agent_sales,0) ELSE 0 END as top_agent_salesvolume
FROM
projects
JOIN
SELECT
a.pid,
a.agent_name as top_agent_name,
a.agent_sales as top_agent_sales
FROM
(SELECT
projects.id as pid,
concat(users.f_name, ' ', users.l_name) as agent_name,
SUM(units.price) AS agent_sales
FROM users
inner join bookings on bookings.agent_id = users.id
inner join units on bookings.unit = units.id
inner join types on types.id = units.types_id
inner join projects on projects.id = types.project_id
WHERE units.status = 'Sold'
GROUP BY pid, users.id
) a # get all agents for all projects
JOIN
(SELECT
MAX(agent_sales) as max_project_agent_sales
FROM
(SELECT
projects.id as pid,
SUM(units.price) AS agent_sales
FROM users
inner join bookings on bookings.agent_id = users.id
inner join units on bookings.unit = units.id
inner join types on types.id = units.types_id
inner join projects on projects.id = types.project_id
WHERE units.status = 'Sold'
GROUP BY pid, users.id
)
GROUP BY pid) b ON a.pid = b.pid
WHERE
a.agent_sales = b.max_project_agent_sales
ORDER BY a.agent_sales desc
Old answer below:
There are 2 topagents for each pid in the inner query since it's a union of 2 group bys. There isn't a reducing function in the outer group by pid so the topagent returned in the select is the first one that came up in the inner query.

SQL query - dynamic sub query

I am having trouble trying to create a query to:
Select all the students who have not completed all peer review's for a particular week.
background: Each week, every student must peer review their peers in the same group.
Each group can be a different size, which is the problem I am having.
this is my current test data:
Table 1: peer review table
Table 2: student table.
This is my inital query, groups all the students based on the amount of peer review's they've made. I now need to to check if the count(*) is less than the size of the group for each student :
SELECT *
FROM peerreview
RIGHT JOIN student
ON student. studentID = peerreview.reviewer
WHERE week = 11
GROUP BY studentID
HAVING Count(*) < ????
Following query will return the student which has reviewed all the students in same group.
SELECT a.reviewer,
a.groupid
FROM (SELECT student2.studentID AS reviewer,
student1.groupid,
Count(*) AS cnt
FROM student student1
INNER JOIN peerreview
ON student1.studentID = peerreview.reviewee
INNER JOIN STUDENT STUDENT2
ON student2.studentID = peerreview.reviewer
WHERE student2.groupid = student2.groupid
AND peerreview.week = 11
GROUP BY student1.groupid,
student2.studentID) a
INNER JOIN (SELECT groupid,
Count(*) - 1 AS cnt
FROM student
GROUP BY groupid) b
ON a.groupid = b.groupid
AND a.cnt = b.cnt
See SqlFiddle
Select S.StudentId As Reviewer
, S1.StudentId As StudentYetToBeReviewed
, Weeks.WeekNum
From Student As S
Join Student As S1
On S1.GroupId = S.GroupId
And S1.StudentId <> S.StudentId
Cross Join (
Select 7 As WeekNum
Union All Select 11
) As Weeks
Where Not Exists (
Select 1
From PeerReview As P1
Where P1.reviewee = S1.StudentId
And P1.Week = Weeks.WeekNum
)
Order By WeekNum, reviewer
This provides you a list, by week, of the reviewer and the person they need to review. In the real solution, you would want to replace the Cross Join of weeks with a distinct list of weeks in which reviews should happen.
SQL Fiddle version
select distinct s1.*
from student s1 inner join student s2 on s1.groupId = s2.groupeId
left join peerreview pr on pr.revieweer = s1.studentId
and pr.reviewee = s2.studentId
where pr.Week = ? and pr.revieweer is null and s1.studentId <> s2.studentId