I have 3 tables like this:
table_events
+------+----------+----------------------+
| ID | Title | Employees |
+------+----------+----------------------+
| 1 | Event1 | john,james |
+------+----------+----------------------+
| 2 | Event2 | sarah,jessica |
+------+----------+----------------------+
table_check_in
+------+----------+----------+---------------------+
| ID | Time | EventID | By |
+------+----------+----------+---------------------+
| 1 | 08:30 | 1 | john |
+------+----------+----------+---------------------+
| 2 | 08:30 | 1 | james |
+------+----------+----------+---------------------+
| 3 | 09:30 | 1 | john |
+------+----------+----------+---------------------+
| 4 | 10:30 | 2 | sarah |
+------+----------+----------+---------------------+
| 5 | 10:35 | 2 | sarah |
+------+----------+----------+---------------------+
table_problems
+------+----------------+----------+---------------------+
| ID | Comment | EventID | By |
+------+----------------+----------+---------------------+
| 1 | Broken door | 1 | john |
+------+----------------+----------+---------------------+
| 2 | Slippery floor | 1 | john |
+------+----------------+----------+---------------------+
| 3 | Leaking tap | 1 | john |
+------+----------------+----------+---------------------+
| 4 | Broken window | 2 | jessica |
+------+----------------+----------+---------------------+
| 5 | Broken glass | 2 | jessica |
+------+----------------+----------+---------------------+
I would like to print something like this:
+------+----------+---------------+-------------------+-------------------+
| ID | Title | Employees | Count_Check_In | Count_Problems |
+------+----------+---------------+-------------------+-------------------+
| 1 | Event1 | john,james | john:2,james:1 | john:3,james:0 |
+------+----------+---------------+-------------------+-------------------+
| 2 | Event2 | sarah,jessica | sarah:2,jessica:0 | sarah:0,jessica:2 |
+------+----------+---------------+-------------------+-------------------+
I know this problem would be trivial if the database was designed properly, but we don't have the luxury of an application rewrite at the moment.
You need to initially get all the employees for each event id from check in and problem tables by using a union.
Then left join the counts from each of check in and problems table to the previous result to get the 0 counts as well.
Finally use a group_concat to get the result in one row for each event id.
select te.id,te.title,te.employees
,group_concat(concat(t.`By`,':',coalesce(tccnt.cnt,0))) count_check_in
,group_concat(concat(t.`By`,':',coalesce(tpcnt.cnt,0))) count_problems
from table_events te
left join (select eventid,`By` from table_check_in
union
select eventid,`By`from table_problems) t on te.id = t.eventid
left join (select eventid,`By`,count(*) cnt from table_check_in group by eventid,`By`) tccnt on tccnt.eventid = t.eventid and tccnt.`By`=t.`By`
left join (select eventid,`By`,count(*) cnt from table_problems group by eventid,`By`) tpcnt on tpcnt.eventid = t.eventid and tpcnt.`By`=t.`By`
group by te.id,te.title,te.employees
Sample Demo (thanks to #valex for setting up the schema)
You can use GROUP_CONCAT to get a result. Here is an example. The only thing missed is employees with 0 check ins or problems.
SELECT ID, Title,Employees,
GROUP_CONCAT(DISTINCT CONCAT(check_in.`By`,':',check_in.cnt))
as Count_Check_In,
GROUP_CONCAT(DISTINCT CONCAT(problems.`By`,':',problems.cnt))
as Count_Problems
FROM table_events
LEFT JOIN (SELECT EventID,`By`, COUNT(*) as cnt
FROM table_check_in
GROUP BY EventID,`By`) as check_in
ON table_events.ID = check_in.EventID
LEFT JOIN (SELECT EventID,`By`, COUNT(*) as cnt
FROM table_problems
GROUP BY EventID,`By`) as problems
ON table_events.ID = problems.EventID
GROUP BY table_events.id
Demo
Related
I have a MySQL 5.6 database with 3 tables:
job_offer
+----+----------+-------------+-----------+
| id | name | position_id | status_id |
+----+----------+-------------+-----------+
| 1 | John | 1 | 4 |
| 2 | Smith | 1 | 4 |
| 3 | Williams | 2 | 2 |
+----+----------+-------------+-----------+
position
+----+----------+
| id | name |
+----+----------+
| 1 | frontend |
| 2 | backend |
+----+----------+
status
+----+-----------+
| id | name |
+----+-----------+
| 1 | contacted |
| 2 | declined |
| 3 | rejected |
| 4 | interview |
+----+-----------+
I would like to build a query that can count all job offers by their position and statuses.
I have this query that performs almost the way I want it:
SELECT
position.name AS position_name,
status.name AS status_name
COUNT(job_offer.id) AS offers
FROM
job_offer
LEFT OUTER JOIN
position
ON job_offer.position_id = position.id
LEFT OUTER JOIN
status
ON job_offer.status_id = status.id
GROUP BY
position_name, status_name
Which gives me this result:
+---------------+-------------+--------+
| position_name | status_name | offers |
+---------------+-------------+--------+
| frontend | interview | 2 |
| backend | declined | 1 |
+---------------+-------------+--------+
The only problem is that I also need to display all existing statuses related to positions regardless of being NULL. So ideally it should look like this:
+---------------+-------------+--------+
| position_name | status_name | offers |
+---------------+-------------+--------+
| frontend | contacted | 0 |
| frontend | declined | 0 |
| frontend | rejected | 0 |
| frontend | interview | 2 |
| backend | contacted | 0 |
| backend | declined | 1 |
| backend | rejected | 0 |
| backend | interview | 0 |
+---------------+-------------+--------+
Is it possible to achieve this with one query? Thanks in advance for any help.
We can use a cross join approach between the position and status table to generate all possible combinations. Then, left join to job_offer and aggregate by position and status to find the counts:
SELECT
p.name AS position_name,
s.name AS status_name,
COUNT(jo.id) AS offers
FROM position p
CROSS JOIN status s
LEFT JOIN job_offer jo
ON jo.position_id = p.id AND
jo.status_id = s.id
GROUP BY
p.name,
s.name
ORDER BY
p.name,
s.name;
Demo
I have 2 tables,but linked in many to many relations so 3 tables :
Table Author :
idAuthor,
Name
+----------+-------+
| idAuthor | Name |
+----------+-------+
| 1 | Renee |
| 2 | John |
| 3 | Bob |
| 4 | Bryan |
+----------+-------+
Table Publication:
idPublication,
Title,
Type,
Date,
Journal,
Conference
+---------------+--------------+------+-------------+------------+-----------+
| idPublication | Title | Date | Type | Conference | Journal |
+---------------+--------------+------+-------------+------------+-----------+
| 1 | Flower thing | 2008 | book | NULL | NULL |
| 2 | Bees | 2009 | article | NULL | Le Monde |
| 3 | Wasps | 2010 | inproceding | KDD | NULL |
| 4 | Whales | 2010 | inproceding | DPC | NULL |
| 5 | Lyon | 2011 | article | NULL | Le Figaro |
| 6 | Plants | 2012 | book | NULL | NULL |
+---------------+--------------+------+-------------+------------+-----------+
Table author_has_publication :
Author_idAuthor,
Publication_idPublication
+-----------------+---------------------------+
| Author_idAuthor | Publication_idPublication |
+-----------------+---------------------------+
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 1 | 5 |
| 2 | 5 |
| 3 | 5 |
| 3 | 6 |
+-----------------+---------------------------+
What I want to do is get the top X author having the most publications.
I achieved to get the result avec the idAuthor having the most publications, using this request :
SELECT Author_idAuthor, COUNT(*) as count FROM Author_has_publication GROUP BY Author_idAuthor ORDER BY count DESC;
I get the list of the authors id, ordered by the number of publications :
+-----------------+-------+
| Author_idAuthor | count |
+-----------------+-------+
| 3 | 3 |
| 2 | 2 |
| 1 | 2 |
| 4 | 1 |
+-----------------+-------+
but then when I try to select the author corresponding to the top X of the result set of the previous query I have an error
I am Trying this SELECT TOP 2 FROM author WHERE (SELECT Author_idAuthor, COUNT(*) as count FROM Author_has_publication GROUP BY Author_idAuthor ORDER BY count DESC)=idAuthor;
I think it might be because my inside query return 2 rows, and I do a simple SELECT here or that I need a JOIN but i have no ideas how to use it here.
MySQL has no TOP keyword. It does however have a LIMIT keyword. Your query is invalid anyway.
There are a couple of options here. The following is an example of a correlated subquery: https://en.wikipedia.org/wiki/Correlated_subquery
SELECT
a.idAuthor,
a.Name ,
(SELECT COUNT(*) from author_has_publication ahp WHERE
ahp.Author_idAuthor = a.idAuthor) AS publication_count
FROM
author a
ORDER BY
publication_count DESC
LIMIT 2
As the referenced article notes, the above is inefficient as the subquery needs to be re-executed for each row of the result. If you do not actually need the count in the resultset then the below would be more efficient as the subquery is non-correlated and executed only once.
SELECT
a.idAuthor,
a.Name
FROM
author a
INNER JOIN
(select ahp.Author_idAuthor AS idAuthor, COUNT(*) as publication_count
FROM author_has_publication ahp GROUP BY ahp.Author_idAuthor LIMIT 2)
AS TEMP ON TEMP.idAuthor = a.idAuthor
This question already has answers here:
MySQL DISTINCT on a GROUP_CONCAT()
(6 answers)
Closed 6 years ago.
I have a question about how to merge multiple row output into one row without having the same entry multiple times.
The basic setup is 4 tables:
room
appointments
users
actions
And 2 intermediate tables:
actions_appointments
users_appointments
I post the exact structure of the tables at the end of my post.
Multiple appointments can be made for one entry in the room table (n:1), but one or more users can join appointments (n:n) and one or more actions can be performed (n:n).
The problem is that I don't know how to output a single appointment with each user and action only being displayed ONCE per appointment.
With the example tables at the bottom of this post I basically want this to be my output:
|----------------|-----------|---------------------|-------------|------------------------|
| appointment_id | room_name | datetime | actions | userfullnames |
|----------------|-----------|---------------------|-------------|------------------------|
| 1 | Studio | 2016-09-01 15:30:00 | work, sleep | John Doe, Martin Smith |
| 2 | Office | 2017-04-02 13:00:00 | sleep | John Doe |
|----------------|-----------|---------------------|-------------|------------------------|
But with the queue I came up with I get this:
|----------------|-----------|---------------------|-------------|------------------------|
| appointment_id | room_name | datetime | actions | userfullnames |
|----------------|-----------|---------------------|-------------|------------------------|
| 1 | Studio | 2016-09-01 15:30:00 | work, sleep,| John Doe, Martin Smith,|
| | | | work, sleep | John Doe, Martin Smith |
| 2 | Office | 2017-04-02 13:00:00 | sleep | John Doe |
|----------------|-----------|---------------------|-------------|------------------------|
I mean I kinda get that I screwed up my joins but I'm totally stuck at the moment. Any hints? I feel like the solution is simple but I'm totally blind at the moment.
My queue:
SELECT
appointments.id AS 'appointment_id',
room.name AS 'room_name',
appointments.datetime,
GROUP_CONCAT(actions.name SEPARATOR ', ') AS 'actions',
GROUP_CONCAT(users.givenname, ' ', users.surname SEPARATOR ', ') AS 'userfullnames'
FROM appointments
INNER JOIN actions_appointments
ON appointments.id = actions_appointments.appointments_id
INNER JOIN actions
ON actions_appointments.actions_id = actions.id
INNER JOIN users_appointments
ON users_appointments.appointments_id = appointments.id
INNER JOIN users
ON users_appointments.users_id = users.id
INNER JOIN room
ON appointments.room_id = room.id
GROUP BY
appointments.id;
Table structure:
The basic tables:
|-------------------|
| room |
|-------------------|
| id | name |
|--------|----------|
| 1 | Office |
| 2 | Studio |
|-------------------|
|----------------------------------------|
| appointments |
|--------|---------|---------------------|
| id | room_id | datetime |
|--------|---------|---------------------|
| 1 | 2 | 2016-09-01 15:30:00 |
| 2 | 1 | 2017-04-02 13:00:00 |
|--------|---------|---------------------|
|-----------------------------------------|
| users |
|-----------------------------------------|
| id | username | givenname | surname |
|--------|----------|-----------|---------|
| 1 | j.doe | John | Doe |
| 2 | m.smith | Martin | Smith |
|--------|----------|-----------|---------|
|--------------------|
| actions |
|--------------------|
| id | name |
|--------|-----------|
| 1 | work |
| 2 | sleep |
|--------------------|
The intermediate tables:
|------------------------------|
| actions_appointments |
|------------------------------|
| actions_id | appointments_id |
|------------|-----------------|
| 1 | 1 |
| 2 | 1 |
| 2 | 2 |
|------------|-----------------|
|----------------------------|
| users_appointments |
|----------------------------|
| users_id | appointments_id |
|----------|-----------------|
| 1 | 1 |
| 2 | 1 |
| 1 | 2 |
|----------|-----------------|
Edit: The correct queue with DISTINCT
Thanks to Juan.Queiroz and Mike!
SELECT
appointments.id AS 'appointment_id',
room.name AS 'room_name',
appointments.datetime,
GROUP_CONCAT(DISTINCT actions.name SEPARATOR ', ') AS 'actions',
GROUP_CONCAT(DISTINCT users.givenname, ' ', users.surname SEPARATOR ', ') AS 'userfullnames'
FROM appointments
INNER JOIN actions_appointments
ON appointments.id = actions_appointments.appointments_id
INNER JOIN actions
ON actions_appointments.actions_id = actions.id
INNER JOIN users_appointments
ON users_appointments.appointments_id = appointments.id
INNER JOIN users
ON users_appointments.users_id = users.id
INNER JOIN room
ON appointments.room_id = room.id
GROUP BY
appointments.id;
GROUP BY
appointments.id,
room.name,
appointments.datetime
So in order to know how many people in a table are called Johnny I would need to excecute the following query.
Query:
Select count(*) from mytable where first = 'Johnny';
It would give me 2 as the result.
What I wish to do however is record this number in the count column so that the end result comes out like this.
+--------+----------+
| First | COUNT |
+--------+----------+
| Johnny | 2 |
| Diane | 1 |
| Johnny | 2 |
| Harold | 1 |
| Amy | 3 |
| Roy | 2 |
| Amy | 3 |
| Amy | 3 |
| Roy | 2 |
+--------+----------+
Is there any query or procedure capable of resulting in this type of output?
To get your exact output, you need to use a subquery:
select
mytable.First,
counts.`COUNT`
from
mytable
join (
select
First,
count(*) `COUNT`
from
mytable
group by
First
) counts on mytable.First = counts.First;
Try this:
SELECT T1.First, T2.COUNT
FROM mytable T1 JOIN
(SELECT First, COUNT(*) as COUNT
FROM mytable
GROUP BY First) as T2 ON T1.First=T2.First
The result will be:
+--------+----------+
| First | COUNT |
+--------+----------+
| Johnny | 2 |
| Diane | 1 |
| Johnny | 2 |
| Harold | 1 |
| Amy | 3 |
| Roy | 2 |
| Amy | 3 |
| Amy | 3 |
| Roy | 2 |
+--------+----------+
I have 3 tables to join and need some help to make it work, this is my schema:
donations:
+--------------------+------------+
| uid | amount | date |
+---------+----------+------------+
| 1 | 20 | 2013-10-10 |
| 2 | 5 | 2013-10-03 |
| 2 | 50 | 2013-09-25 |
| 2 | 5 | 2013-10-01 |
+---------+----------+------------+
users:
+----+------------+
| id | username |
+----+------------+
| 1 | rob |
| 2 | mike |
+----+------------+
causes:
+--------------------+------------+
| id | uid | cause | <missing cid (cause id)
+---------+----------+------------+
| 1 | 1 | stop war |
| 2 | 2 | love |
| 3 | 2 | hate |
| 4 | 2 | love |
+---------+----------+------------+
Result I want (data cropped for reading purposes)
+---------+-------------+---------+-------------+
| id | username | amount | cause |
+---------+-------------+---------+-------------+
| 1 | rob | 20 | stop war |
| 2 | mike | 5 | love |
+---------+-------------+-----------------------+
etc...
This is my current query, but returns double data:
SELECT i.*, t.cause as tag_name
FROM users i
INNER JOIN donations tti ON (tti.uid = i.id)
INNER JOIN causes t ON (t.uid = tti.uid)
EDIT: fixed sql schema on fiddle
http://sqlfiddle.com/#!2/0e06c/1 schema and data
How I can do this?
It seems your table's model is not right. There should be a relation between the Causes and Donations.
If not when you do your joins you will get duplicated rows.
For instance. Your model could look like this:
Donations
+--------------------+------------+
| uid | amount | date | causeId
+---------+----------+------------+
| 1 | 20 | 2013-10-10 | 1
| 2 | 5 | 2013-10-03 | 2
| 2 | 50 | 2013-09-25 | 3
| 2 | 5 | 2013-10-01 | 2
+---------+----------+------------+
causes:
+----------------------+
| id | cause |
+---------+------------+
| 1 | stop war |
| 2 | love |
| 3 | hate |
+---------+------------+
And the right query then should be this
SELECT i.*, t.cause as tag_name
FROM users i
INNER JOIN donations tti ON (tti.uid = i.id)
INNER JOIN causes t ON (t.id = tti.causeId)
Try this
SELECT CONCAT(i.username ,' ',i.first_name) `name`,
SUM(tti.amount),
t.cause AS tag_name
FROM users i
LEFT JOIN donations tti ON (tti.uid = i.id)
INNER JOIN causes t ON (t.uid = tti.uid)
GROUP BY i.id
Fiddle
You need to match the id from both the users and causes table at the same time, like so:
SELECT i.*, t.cause as tag_name
FROM users i
INNER JOIN donations tti ON (tti.uid = i.id)
INNER JOIN causes t ON (t.uid = tti.uid and t.id = i.id)
Apologies for formatting, I'm typing this on a phone.