I have a MySQL table like this:
acco_id | room_id | arrival | amount | persons | available
1 | 1 | 2015-19-12 | 3 | 4 | 1
1 | 2 | 2015-19-12 | 1 | 10 | 1
1 | 1 | 2015-26-12 | 4 | 4 | 1
1 | 2 | 2015-26-12 | 2 | 10 | 1
2 | 3 | 2015-19-12 | 2 | 6 | 0
2 | 4 | 2015-19-12 | 1 | 4 | 1
What im trying to achieve is a single query with a result like:
acco_id | max_persons_available
1 | 22
2 | 4
I tried using a GROUP BY accommodation_id using a query like:
SELECT
accommodation_id,
SUM(amount * persons) as max_persons_available
FROM
availabilities
WHERE
available = 1
GROUP BY
accommodation_id
Only now the result of acco_id uses all arrival dates. When I add arrival to the query no more unique acco_id's.
Does anyone know a good Single SQL which can use the table indexes?
If I'm understanding the question correct (the last part is a bit confusing). You want to have the accomodation id and numbers as you have now but limited to specific arrival dates.
If so the following statement should do exactly that as it is not necessary to put arrival into the select if you "just" use it in the where statement. As else you would need to put it into the group by and thus have non unique accomodation id's.
SELECT
accommodation_id,
SUM(amount * persons) as max_persons_available
FROM
availabilities
WHERE
available = 1 and arrival >= '2015-12-19' and arrival < '2015-10-26'
GROUP BY
accommodation_id
I guess (reading your question) what you are looking for is this but im not sure as your question is a bit unclear:
SELECT
accommodation_id,
arrival,
SUM(amount * persons) as max_persons_available
FROM
availabilities
WHERE
available = 1
GROUP BY
accommodation_id, arrival
Related
This question already has an answer here:
Mysql group by two columns and pick the maximum value of third column
(1 answer)
Closed 2 years ago.
I've been taking too long trying to solve this, I need to filter this table:
+----+-------+-------+
| id | jobID |stageID|
+----+-------+-------+
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 1 | 2 |
| 4 | 1 | 1 |
| 5 | 2 | 2 |
| 6 | 2 | 1 |
| 7 | 2 | 1 |
| 8 | 2 | 2 |
+----+-------+-------+
You see every job has many rows with different stages, I need to get the last row of every stage of every job.
For example, look at job 1. It has 4 rows, each one with a given stage. I'd need to get the last entry of a stage for that job, which means, rows 3 and 4.
So for the full table I need to get rows No. 3, 4, 7 and 8, like this
+----+-------+-------+
| id | jobID |stageID|
+----+-------+-------+
| 3 | 1 | 2 |
| 4 | 1 | 1 |
| 7 | 2 | 1 |
| 8 | 2 | 2 |
+----+-------+-------+
I think I'll go nuts. I try with GROUP_BY but it groups the stages without taking in count the jobs.
Can you help me?
This is simply:
select max(id) as id, jobID, stageID
from yourtable
group by jobID, stageID
If you need additional information selected, use that as a subselect:
select yourtable.id, yourtable.jobID, yourtable.stageID, yourtable.other
from (
select max(id) as id
from yourtable
group by jobID, stageID
) max_job_stage_ids
join yourtable using (id)
or use IN (I find this less helpful in visualizing the query plan, but some people prefer it):
select id, jobID, stageID, other
from yourtable
where id in (select max(id) from yourtable group by jobID, stageID)
I'm sorry for fuzzy title of this question.
I have 2 Tables in my database and want to count records of first_table using "group by" on a foreign key id that exists in a column of second_table (which stores ids like array "1,2,3,4,5").
id | name | fk_id
1 | john | 1
2 | mike | 1
3 | jane | 2
4 | tailor | 1
5 | jane | 3
6 | tailor | 5
7 | jane | 4
8 | tailor | 5
9 | jane | 5
10 | tailor | 5
id | name | fk_ids | s_fk_id
1 | xxx | 1,5,6 | 1
2 | yyy | 2,3 | 1
3 | zzz | 9 | 1
4 | www | 7,8 | 1
Now i wrote the following query but it not working properly and displays wrong numbers.
I WANT TO:
1-Count records in first_table group by "fk_id"
2-Sum the counted records which exists in "fk_ids"
3-Display the sum result (sum of related counts) grouped by id.
symbol ' ' means ``.
select sum(if(FIND_IN_SET('fk_id', 'fk_ids')>0,'count',0) 'sum', 'count', 'from'.'fk_id', 'second_table'.* FROM 'second_table'
LEFT JOIN
(
SELECT 'fk_id', count(*) 'count'
FROM 'first_table'
group BY 'fk_id'
) AS 'from'
ON FIND_IN_SET('fk_id', 'fk_ids')>0
WHERE 'second_table'.'s_fk_id'=1
GROUP BY 'id'
ORDER by 'count' DESC
This table has many data and we have no plan to change the structure.
Edit:
Desired output:
id | name | sum
1 | xxx | 7 (3+4+0)
2 | yyy | 2 (1+1)
3 | zzz | 0 (0)
4 | www | 0 (0+0)
After two holidays i came back to work and found out that the "FIND_IN_SET" function is not working properly with space contained string.
And the problem is that i was ignored the spaces too, (same as this question)
Finnaly this query worked:
select sum(`count`) `sum`, `count`, `from`.`fk_id`, `second_table`.* FROM `second_table`
LEFT JOIN
(
SELECT `fk_id`, count(*) `count`
FROM `first_table`
group BY `fk_id`
) AS `from`
ON FIND_IN_SET(`fk_id`, replace(`fk_ids`,' ',''))>0
WHERE `second_table`.`s_fk_id`=1
GROUP BY `id`
ORDER by `count` DESC
And the magic is replace(fk_ids,' ','')
I have 2 different tables called observations and intervals.
observations:
id | type, | start
------------------------------------
1 | classroom | 2017-06-07 16:18:40
2 | classroom | 2017-06-01 15:12:00
intervals:
+----+----------------+--------+------+---------------------+
| id | observation_id | number | task | time |
+----+----------------+--------+------+---------------------+
| 1 | 1 | 1 | 1 | 07/06/2017 16:18:48 |
| 2 | 1 | 2 | 0 | 07/06/2017 16:18:55 |
| 3 | 1 | 3 | 1 | 07/06/2017 16:19:00 |
| 4 | 2 | 1 | 3 | 01/06/2017 15:12:10 |
| 5 | 2 | 2 | 1 | 01/06/2017 15:12:15 |
+----+----------------+--------+------+---------------------+
I want a view that will display:
observation_id | time_on_task (total time in seconds where task = 1)
1 | 13
2 | 5
So I must first check to see if the first observation has task = 1, if it is I must record the difference between the current interval and the start from the observations table, then add that to the total time. From there on after if the task = 1, I just add the time difference from the current interval and previous interval.
I know I can use:
select observation_id, TIME_TO_SEC(TIMEDIFF(max(time),min(time)))
from your_table
group by observation_id
to find the total time in the intervals table between all intervals outside of the first one.
But
1. I need to only include interval times where task = 1. (The endtime for the interval is the one listed)
2. Need the timediff between the first interval and initial start (from observations table) if number = 1
I'm still new to the Stackoverflow community, but you could try to use SQL
LAG() function
For instance
Using an outer Select Statement
SELECT COl1, COL2, (DATEDIFF(mi, Inner.prevtime, Currentdatetime,0)) AS Difference
FROM ( SELECT LAG(Created_Datetime) OVER (ORDER BY Created_Datetime) AS prevtime
From MyTable
Where SomeCondition) as Inner
Sorry if it looks goofy, still trying to learn to format code here.
https://explainextended.com/2009/03/12/analytic-functions-optimizing-lag-lead-first_value-last_value/
Hope it helps
I realize this question has been asked quite a few times, however i haven't managed to find a working solution for my case.
Essentially my problem arises because MySQL Doesn't allow sub-querys in views.
I found a few workarounds but they don't seem to work.
In more detail...
My first table (competitions) stores a users competitions:
id_tournament | id_competition | id_user | result
-------------------------------------------------
1 | 1 | 1 | 10
1 | 1 | 2 | 30
1 | 2 | 1 | 20
1 | 2 | 3 | 50
1 | 3 | 2 | 90
1 | 3 | 3 | 100
1 | 3 | 4 | 85
In this example there are three competitions:
(
user1 vs. user2,
user1 vs. user3,
user2 vs. user3 vs. user4
)
My problem is that i need to define a view that gives me the winners in each competition.
Expected Result:
id_tournament | id_competition | id_winner
------------------------------------------
1 | 1 | 2
1 | 2 | 3
1 | 3 | 3
This can be solved with the query:
SELECT
id_tournament,
id_competition,
id_user as id_winner
FROM (
SELECT * FROM competitions ORDER BY result DESC
) x GROUP BY id_tournament, id_competition
This query however uses a subquery (not allowed in views), so my first solution was to define a 'helper view'as :
CREATE VIEW competitions_helper AS (
SELECT * FROM competitions ORDER BY result DESC
);
CREATE VIEW competition_winners AS (
SELECT
id_tournament,
id as id_competition,
id_user as winner
FROM competitions_helper GROUP BY id_tournament, id_competition
);
However this does not seem to give the correct result.
It's result will then be:
id_tournament | id_competition | id_winner
------------------------------------------
1 | 1 | 1
1 | 2 | 1
1 | 3 | 1
What i don't understand is why it works when i use Sub-querys and why it gives a different result with the exact same statement in a view.
Any help is appreciated, thanks alot.
This is due to the GROUP BY behaviour.
In this case, the server is free to choose any value from each group, so unless they are the same, the values chosen are indeterminate, which is probably not what you want.
I would solve the problem in this way:
CREATE VIEW competitions_helper AS (
SELECT id_tournament,
id_competition,
MAX(result) as winning_result
FROM competitions
GROUP BY id_tournament,
id_competition
);
CREATE VIEW competition_winners AS (
SELECT c.id_tournament,
c.id_competition,
c.id_user
FROM competitions c
INNER JOIN competitions_helper ch
ON ch.id_tournament = c.id_tournament
AND ch.id_competition = c.id_competition
AND ch.winning_result = c.result
);
I'm trying to do something like 'select groupwise maximum', but I'm looking for groupwise order number.
so with a table like this
briefs
----------
id_brief | id_case | date
1 | 1 | 06/07/2010
2 | 1 | 04/07/2010
3 | 1 | 03/07/2010
4 | 2 | 18/05/2010
5 | 2 | 17/05/2010
6 | 2 | 19/05/2010
I want a result like this
breifs result
----------
id_brief | id_case | dateOrder
1 | 1 | 3
2 | 1 | 2
3 | 1 | 1
4 | 2 | 2
5 | 2 | 1
6 | 2 | 3
I think I want to do something like described here MySQL - Get row number on select, but I don't know how I would reset the variable for each id_case.
This will give you how many records are there with this id_case value and a date less than or equal to this date value.
SELECT t1.id_brief,
t1.id_case,
COUNT(t2.*) AS dateOrder
FROM yourtable AS t1
LEFT JOIN yourtable AS t2 ON t2.id_case = t1.id_case AND t2.date <= t1.date
GROUP BY t1.id_brief
Mysql is permissive about columns which can be queries using GROUP BY. With a more stric DBMS you may need GROUP BY t1.id_brief, t1.id_case.
I strongly advise you to have the right indexes on the table:
CREATE INDEX filter1 ON yourtabl (id_case, date)