I have three tables:
TABLE 1 contracts
-------------------
id | contract_name
--------------------
1 test name
2 test name 2
2 test name 3
4 test name 4
TABLE 2 rooms
-------------------
id | room_name
--------------------
1 test name
2 test name 2
2 test name 3
4 test name 4
TABLE 3 promos
----------------------------------
id | contracts_id | rooms_id
----------------------------------
1 1,3 1,3,4
1 2 1,2,3
No I am trying to do an inner join to get the names of the contract and the rooms according to the ids in the array saved in database. I know this is not ideal at all, but I can not change the database set up. So here is what I would like to do with my query, but obviously it is impossible. Does anyone have any idea on how I can accomplish this?
mysql_query("SELECT pb.*, c.contract_name, r.room_name FROM promo_blackouts AS pb
INNER JOIN contracts as c ON c.contract_id IS IN pb.contracts_id
INNER JOIN rooms as r ON r.room_id IS IN pb.rooms_id
WHERE pb.promo_id = '$promo_id'") or die(mysql_error());
Are you looking for something like this?:
SELECT DISTINCT
contract_name,
room_name
FROM
promos
INNER JOIN
contracts ON FIND_IN_SET(contracts.id, contract_id) != 0
INNER JOIN
rooms ON FIND_IN_SET(rooms.id, room_id) != 0
WHERE
promos.id = 1
Related
I have a table in which I want to compare an ID column with another column in the same table.
This is my table
ID | Name | BossID
1 John 3
2 Max 4
3 Peter 4
4 Alex 5
For example I want to use
select * from mytable where ID = BossID
and I expected to get that Peter is the Boss of John and Alex is the Boss of Max and Peter, but when I use it this way, I dont get any info on the query...
Any idea to get it?
The expected query result are:
ID | Name | BossID
1 John 3
2 Max 4
3 Peter 4
seems like you want the list of employees who their boss exists in the list as well:
select *
from mytable
where bossid in (select id from mytable);
to get the boss name :
select t.ID, t.Name, b.Name as BossName
from mytable t
join mytbale b
on t.bossid = b.id
you can use left join to return all the employees in the list
I am creating a database to store music.
There are different categories that each have sub categories. Example:
id name parentID
1 instrumentation null
2 solo_instrument null
3 Concert Band 1
4 Brass Band 1
5 Fanfare Band 1
6 Clarinet 2
7 Saxophone 2
8 Trumpet 2
On the other hand I have a table that stores the musicID that is linked to a categoryID
id categoryID musicID
1 4 1
2 8 1
3 3 2
4 6 2
I need the following result from a query:
musicID instrumentation solo_instrument
1 Brass Band Trumpet
2 Concert Band Clarinet
I have been told to use a tree structure as in the future it is likely that other categories are added and this should be able to support that. However, I am not able to figure out how to write a query to get the result above.
I kind of get the result I want when selecting first the instrumentation, second the solo_instrument, but this is all hardcoded and does not allow for music tracks to only have one parentID as I select them individually.
Is this even possible or should I overhaul my database structure? I'd like to see your recommendations.
You should be able to tackle this using conditional aggregation.
Query :
SELECT
mu.musicID,
MAX(CASE WHEN cp.name = 'instrumentation' THEN ca.name END) instrumentation,
MAX(CASE WHEN cp.name = 'solo_instrument' THEN ca.name END) solo_instrument
FROM
musics mu
INNER JOIN categories ca ON ca.id = mu.categoryID
INNER JOIN categories cp ON cp.id = ca.parentID
GROUP by mu.musicID
The INNER JOINs pull up the corresponding category, and then goes up one level to find the parent category. If new root categories are created, you would just need to add more MAX() columns to the query.
In this DB Fiddle demo with your sample data, the query returns :
| musicID | instrumentation | solo_instrument |
| ------- | --------------- | --------------- |
| 1 | Brass Band | Trumpet |
| 2 | Concert Band | Clarinet |
First you group by musicid in table_music and the join twice to table_categories:
select t.musicid, c1.name instrumentation, c2.name solo_instrument
from (
select musicid, min(categoryid) instrumentationid, max(categoryid) solo_instrumentid
from table_music
group by musicid
) t inner join table_categories c1
on c1.id = t.instrumentationid
inner join table_categories c2
on c2.id = t.solo_instrumentid
order by t.musicid
I'm stuck for hours on an issue that might be pretty simple to solve but I'm just so lost...
I got 3 tables :
user
id name
----------
1 jack
2 john
...
car
id name
----------
1 ford
2 fiat
3 alfa
4 lada
...
user_car
id_user id_car
-----------------
1 2
1 4
2 1
2 2
2 3
For example, i want to get all users with cars which have id 1 AND 2 in the user_car table so I should get the id_user 2 only and I can't find the proper way to do it.
try this untested query:
select * from user join user_car car1 on id =car1.user_id
join user_car car2 on id =car2.user_id where car1.id_car=1 and car2.id_car=2
I would use UNION for this matter:
SELECT id as id_user from user where id in(1, 2)
UNION
SELECT id as id_car from car where id in (1, 2)
You can use COUNT to do this:-
SELECT user.name
FROM user
INNER JOIN user_car ON user.id = user_car.id_user
INNER JOIN car ON user_car.id_car = car.id
WHERE car.id IN (1,2)
GROUP BY user.name
HAVING COUNT(DISTINCT car.id) = 2
Note that this could be simplified to remove the need for the car table when you are just using the id of the car.
May be you want this
SELECT *
FROM USER
WHERE id IN
(SELECT id_user
FROM user_car
WHERE id_car=1 OR id_car=2);
table 1
--------
pid | name
1 someone
2 another
table2
--------
bid | valu
1 drum
2 guitar
3 flower
4 cake
table3
------
id | pid | bid | pref
1 1 3 yes
2 1 1 maybe
3 1 2 no
4 2 4 definately
5 2 2
6 2 3 no
So as you can see I have 3 simple tables where the third one is used to create a mapping between table 1 and 2 along with some additional data. Now I need to write a query to display the valu and pref in a concatenated string based on the pid,
So against pid = 1, the expected output is something like
flower yes, drum maybe, guitar no....so How do I write this query?
I tried( pretty much a blind guess):
SELECT opa.name, GROUP_CONCAT(CONCAT(opb.valu,' ',opc.pref) SEPARATOR ',') AS myChoice
From
table_1 opa
INNER JOIN table_3 opc ON opc.pid = opa.pid
INNER JOIN table_2 opb ON opb.bid = opc.bid
Any help is appreciated.
your query is right you just forgot the GROUP BY
SELECT opa.name, GROUP_CONCAT(CONCAT(opb.valu,' ',opc.pref) SEPARATOR ',') AS myChoice
From
table1 opa
INNER JOIN table3 opc ON opc.pid = opa.pid
INNER JOIN table2 opb ON opb.bid = opc.bid
group by opc.pid
DEMO HERE
I tried to work out around this. But I think I am getting no where.
I have 3 tables:
This tale contains all questions and question types:
Table: Ref
id | type | info
==========================
1 SS Education
---------------------------
2 RB Gender
---------------------------
3 ST State
This table contains "options" for the questions in the above table 'Ref`
Table: ref_ans
id | q_id | answer_text
===========================
1 1 Masters
---------------------------
2 1 Bachelors
---------------------------
3 1 Undergrad
---------------------------
4 2 Male
---------------------------
5 2 Female
---------------------------
6 2 Dont want to disclose
This table contains states (type ="ST" in table Ref)
Table: us_states
id | answer_text
===========================
1 Alaska
---------------------------
2 Alabama
---------------------------
3 Arkansan
---------------------------
4 Arizona
---------------------------
5 Baltimore
---------------------------
etc
The result I want is:
ref.id, ref_ans.id, ref.answer_text / us_states.answer_text
*for a given ref.question_id *.
And the condition is: If the question_id, for which the answers requested is 'ST', it should pull the answers from us_states, otherwise, it should pull from ref-ans table.
I tried this. Obviously, this did not work:
SELECT ref.id,
CASE WHEN ref.type = 'ST' THEN
(SELECT ID, answer_text FROM us_states )
ELSE
(SELECT id, answer_text FROM ref_ans)
END
FROM ref
WHERE ref.ID = <id>
Any ideas?
Try:
SELECT a.id,
COALESCE(b.id, c.id) AS ans_id,
COALESCE(b.answer_text, c.answer_text) AS answer_text
FROM ref a
LEFT JOIN ref_ans b ON a.id = b.q_id
LEFT JOIN us_states c ON a.type = 'ST'
WHERE a.id = <id> AND (
(a.type <> 'ST' AND b.id IS NOT NULL) OR
(a.type = 'ST' AND c.id IS NOT NULL)
)
Assuming all the three tables are connected by id(1st column):
SELECT ref_ans.id, ref.id, if(ref.type='ST', us_states.answer_text, ref_ans.answer_text) as answer_text
FROM ref_ans
JOIN ref on ref.id=ref_ans.id
JOIN us_states on ref.id=us_states.id
WHERE ref_ans.q_id = <id>