i need to get into select last values (with highest IDa) with specific identifier (IDb).
For example - input:
|IDa|IDb| text
================
| 1 | 1 | What
| 2 | 2 | code
| 3 | 1 | should
| 4 | 2 | I
| 5 | 2 | write
| 6 | 3 | here
| 7 | 2 | ?
wanted output:
|IDa|IDb| text
================
| 3 | 1 | should
| 7 | 2 | ?
| 6 | 3 | here
Thank you for any help.
If IDa is set to auto_increment you can use a self join
select t.*
from t
join (select max(IDa) IDa,IDb from t group by IDb ) t1
using(IDa,IDb) /* is equivalent to on(t.IDa = t1.IDa and t.IDb = t1.IDb) */
order by t.IDb
Also in your expected result set you have mentioned what for IDb 1 and according to your question there should be the word should because its the last one for IDb 1
Fiddle Demo
Related
I'm stuck and I can't figure it out, so I would appreciate any help.
At this point i have table journal which consists of columns:
id | name | type(int) | classification | data | journalUser | start_date(default NULL)
1 | John | 1 | 2 | data123 | 1 | 10-11-2019
2 | Peter | 2 | 2 | data123 | 1 | 10-11-2019
3 | Ash | 2 | 2 | data123 | NULL | NULL
4 | BUBU | 2 | 2 | data123 | 3 | 10-11-2019
I want to make query where I select all, but with exceptions, for example: SELECT * from journal, but if column type = 2, than select this row too if journalUser = 1 AND second check if column type = 2 and start_date IS NULL, than select this row too.
As the result, from table above, from query I wan to get result
id | name | type(int) | classification | data | journalUser | start_date(default NULL)
1 | John | 1 | 2 | data123 | 1 | 10-11-2019
2 | Peter | 2 | 2 | data123 | 1 | 10-11-2019
3 | Ash | 2 | 2 | data123 | NULL | NULL
That's a specific case when the type is 2.
To get the rows with type = 2 along with either (considering the expected output) journalUser = 1 or start_date = null, this can be written this way :
type = 2 AND (journalUser = 1 OR start_date IS NULL)
To make sure you have others type too, you can add an OR condition such as :
OR type <> 2.
This will give this query :
SELECT *
FROM journal
WHERE (type = 2 AND (journalUser = 1 OR start_date IS NULL))
OR type <> 2
I have all those tables above.
car_model_tbl
-----------------------------
id | car_model_name|status |
-----------------------------
1 | seria_1 | 1 |
-----------------------------
2 | golf_4 | 1 |
-----------------------------
3 | C_Class | 1 |
-----------------------------
4 | golf_5 | 1 |
-----------------------------
5 | seria_2 | 0 |
-----------------------------
car_manufacturer_tbl
-------------------------
id |car_manufactu_name |
-------------------------
1 | bmw |
-------------------------
2 | volkswagen |
-------------------------
3 | mercedes |
-------------------------
car_service_tbl
---------------------------------
id | model_id| service_date |
---------------------------------
1 | 1 | 2018-03-10 |
---------------------------------
2 | 2 | 2018-02-10 |
---------------------------------
3 | 1 | 2018-01-10 |
---------------------------------
4 | 1 | 2017-12-10 |
---------------------------------
5 | 2 | 2017-12-10 |
---------------------------------
6 | 3 | 2018-02-10 |
---------------------------------
7 | 2 | 2018-01-10 |
---------------------------------
9 | 4 | 2018-03-10 |
---------------------------------
10 | 4 | 2018-02-10 |
---------------------------------
11 | 5 | 2018-02-10 |
---------------------------------
car_model_manufacturer_relation
-------------------------------------------------
id | model_id | manufactu_id| service_status |
-------------------------------------------------
1 | 1 | 1 | 1 |
-------------------------------------------------
2 | 5 | 1 | 1 |
-------------------------------------------------
3 | 2 | 2 | 1 |
-------------------------------------------------
4 | 4 | 1 | 1 |
-------------------------------------------------
5 | 2 | 2 | 1 |
-------------------------------------------------
6 | 3 | 3 | 1 |
-------------------------------------------------
I need to update car_model_manufacturer_relation.service_status = '0'
where car_service_tbl.service_date < "2018-03-01".
In this case car_model_manufacturer_relation.service_status of models 2, 3 and 5 should be set to '0' because every car_service_tbl.service_date for these models is smaller than "2018-03-01".
However, for models 1 and 4 car_model_manufacturer_relation.service_status should stay '1' because even that they have records smaller than "2018-03-01" they also have bigger dates ex. "2018-03-10".
I am trying to create a query for this but until now without success.
You'll need to nest a grouped query, to get the MAX date per model, and update from that.
update car_model_manufacturer_relation as cmmr,
(select model_id, max(service_date) as check_date
from car_service_tbl
group by model_id) as cst
set cmmr.service_status = '0'
where cmmr.model_id = cst.model_id
and cst.check_date < "2018-03-01"
Where you're using more than one table and the table names include underscores, I try and alias the tables to make the code a little shorter and easier on the eye, hence the use of cmmr and cst as table aliases.
The MAX date has also been renamed for clarity as check_date. You can of course name this anything you wish.
With sub query:
UPDATE car_model_manufacturer_relation c
LEFT join (SELECT model_id, service_date FROM car_service_tbl ORDER BY service_date DESC LIMIT 1) as s ON s.model_id = c.model_id
SET service_status=0
WHERE c.service_date < "2018-03-01"
#tyro - be careful with your solution, as a LEFT JOIN would update the service status to 0 when there wasn't a service date within the car_service_tbl. You would need to use a full join, rather than just the LEFT JOIN as you suggested in order to update the records correctly I feel.
I have two tables containing fields as below.
Table 1
| SetID | InQty | Day |
| 1 | 10 | 1 |
| 2 | 10 | 2 |
| 3 | 10 | 3 |
Table 2
| SetID | OtQty | Day |
| 1 | 1 | 5 |
| 1 | 2 | 6 |
| 1 | 3 | 7 |
SetID in table 2 is linked with SetId in table 1. Day is placed in place of date, just for convenience only. Expected Output,
| Day | InQty | OtQty |
| 1 | 10 | |
| 5 | | 1 |
| 6 | | 2 |
| 7 | | 3 |
Blank Space can be filled with NULL or Zero.
It appears you are querying ONLY for set ID = 1 otherwise, I would expect to see in/out values for Set 2 and 3. You should be able to get with a simple UNION
select t1.Day, t1.InQty, 0 OutQty
from Table1 t1
where SetID = 1
order by t1.Day
union select t2.Day, 0, t2.OtQty
from Table2 t2
where SetID = 1
Now, if you want totals spanning different "setID"s and keeping them differentiated from each other, just add the setID as a column and also add to the group by clause as well.
Given a join table for m-2-m relationship between booth and user
+-----------+------------------+
| booth_id | user_id |
+-----------+------------------+
| 1 | 1 |
| 1 | 2 |
| 1 | 5 |
| 1 | 9 |
| 2 | 1 |
| 2 | 2 |
| 2 | 5 |
| 2 | 10 |
| 3 | 1 |
| 3 | 2 |
| 3 | 3 |
| 3 | 4 |
| 3 | 6 |
| 3 | 11 |
+-----------+------------------+
How can I get a distinct set of booth records that are common between a subset of user ids? For example, if I am given user_id values of 1,2,3, I expect the result set to include only booth with id 3 since it is the only common booth in the join table above between all user_id's provided.
I'm hoping I'm missing a keyword in MySQL to accompish this. The furthest I've come so far is using ... user_id = all (1,2,3) but this is always returning an empty result set (I believe I understand why it is though).
The SQL query for this will be:
select booth_id from table1 where [user_id]
in (1,2,3) group by booth_id having count(booth_id) =
(select count(distinct([user_id])) from table1 where [user_id] in (1,2,3))
If this could help you creating the MySQL query.
I've got two tables in my database. Table 1 is a list of "timelines" and their corresponding owners and title.
Table 2 is a list of users who have access to the timelines but are followers, not owners.
I'm trying to write a query that outputs the lineID's and corresponding titles that are linked to a userID in either of the two tables.
A query for userID 1 would ideally output:
1 a
2 b
3 c
6 f
Hopefully this isn't too confusing but the purpose is to fill a dynamically generated select box with the LineID and Title for a given UserID...
Table 1 ("owners")
--------------------------
| LineID | UserID | Title |
| 1 | 1 | a |
| 2 | 1 | b |
| 3 | 1 | c |
| 4 | 2 | d |
| 5 | 2 | e |
| 6 | 1 | f |
--------------------------
Table 2 ("followers")
----------------------------
| RowID | LineID | UserID |
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 3 | 1 |
| 4 | 3 | 2 |
| 5 | 2 | 2 |
| 6 | 6 | 1 |
----------------------------
I tried using:
SELECT title
FROM `lines`
LEFT JOIN follow
ON follow.user_id = lines.user_id
WHERE follow.user_id = 1
That ended up producing duplicate rows.
The output I need would ideally be an array consisting of all the lineID's and Titles associated with that userID.
select LineId, Title
from owners
where LineId in (select LineId from followers group by LineId )
order by owners.LineId