I have table in database called fileupload_share.
+----+----------+----------+----------------+----------------------------------+
| id | users_id | files_id | shared_user_id | shared_date |
+----+----------+----------+----------------+----------------------------------+
| 3 | 1 | 1 | 2 | 2013-01-31 14:27:06.523908+00:00 |
| 2 | 1 | 1 | 2 | 2013-01-31 14:25:37.760192+00:00 |
| 4 | 1 | 3 | 2 | 2013-01-31 14:46:01.089560+00:00 |
| 5 | 1 | 1 | 3 | 2013-01-31 14:50:54.917337+00:00 |
I want to count the number of shared_user_id according to the file_id.
For example I want to find with how many users the file with id 1 is shared. The answer is with 2 users(shared_user_id). How can I find that in Django?
file_id = 2 #Here is your file_id variable
fileupload_share.objects.filter(file_id = file_id)
.order_by('shared_user_id').distinct('shared_user_id').count()
As comments below say this example doesn't work on MySQL, because of distinct method on field.
However you can try danihp's method:
file_id = 2 #Here is your file_id variable
fileupload_share.objects.filter(file_id = file_id)
.values_list('shared_user_id', flat=True).distinct().count()
Related
I want to group the rows on the basis of a specific condition.
The table structure is something like this
EmpID | EmpName | TaskId | A_Shift_Status | B_Shift_Status | C_Shift_Status | D_Shift_Status
1 | John | 1 | 1 | null | 2 | 1
1 | John | 2 | 1 | null | 1 | 1
2 | Mike | 3 | 1 | 1 | 2 | 1
2 | Mike | 4 | null | 1 | null | 1
3 | Steve | 5 | null | 1 | 2 | 1
3 | Steve | 6 | 1 | null | 2 | 1
The criteria will be
Done 1
Pending 2
NA 3
The expected output is to group the employees by task and the status will be on the following condition
if ALL tasks are done by any employee then the status will be done
(i.e. 1)
if ANY of the tasks is incomplete then the status will be
incomplete/pending (i.e. 2)
So the desired output will be
EmpID | EmpName | A_Shift_Status | B_Shift_Status | C_Shift_Status | D_Shift_Status
1 | John | 1 | null | 2 | 1
2 | Mike | 1 | 1 | 2 | 1
3 | Steve | 1 | 1 | 2 | 1
So in other terms summary/grouping should only show complete/done (i.e. 1) when all the rows of a particular shift column of an employee have status as complete/done (i.e. 1)
Based on your data (where the criteria are 1, 2 and NULL for n/a), a simple 'group by' the employee, and MAX of the columns, should work e.g.,
SELECT
yt.EmpID,
yt.EmpName,
MAX(yt.A_Shift_Status) AS A_Shift_Status,
MAX(yt.B_Shift_Status) AS B_Shift_Status,
MAX(yt.C_Shift_Status) AS C_Shift_Status,
MAX(yt.D_Shift_Status) AS D_Shift_Status
FROM
yourtable yt
GROUP BY
yt.EmpID,
yt.EmpName;
For the shift statuses
If any of them are 2, it returns 2
otherwise if any of them are 1, it returns 1
otherwise it returns NULL
Notes re 1/2/3 (which was specified as criteria) vs 1/2/NULL (which is in the data)
It gets a little tricker if the inputs are supposed to use 1/2/3 instead of 1/2/NULL. Let us know if you are changing the inputs to reflect that.
If the input is fine as NULLs, but you need the output to have '3' for n/a (nulls), you can put an ISNULL or COALESCE around the MAX statements e.g., ISNULL(MAX(yt.A_Shift_Status), 3) AS A_Shift_Status
Might be very simple, but I've been digging fow a few days now... I just can't figure out how to make this SQL query in Access...
In reference to the tables below, i'm looking for the query that can extract all the ITEMS for a specific Shop (ie 1:Alpha) from a specific GROUP (ie 1:Tools), that are NOT in the report for 2014... in this case ITEMS.IDs 6, 8, 9 and 10!
Tables:
Years
ID | Year
-----------------------------------------------
1 | 2014
2 | 2015
Shops
ID | ShopName
-----------------------------------------------
1 | Alpha
2 | Bravo
Items
ID | StockNbr | Description | GroupID
-----------------------------------------------
1 | 00-1200 | Ratchet 1/4 | 1
2 | 00-1201 | Ratchet 1/2 | 1
3 | 00-1300 | Screwdriver Philips No1 | 1
4 | 01-5544 | Banana | 2
5 | 00-4457 | Apple | 2
6 | 21-8887 | Hammer | 1
7 | 21-6585 | Drill | 1
8 | 21-4499 | Multimeter | 1
9 | 21-5687 | Digital Caliper | 1
10 | 22-7319 | File Set | 1
...
Groups
ID | GroupName
-----------------------------------------------
1 | Tools
2 | Fruits
REPORTS
ID | YearID | ShopID | ItemID
-----------------------------------------------
1 | 1 | 1 | 1
2 | 1 | 1 | 2
3 | 1 | 1 | 3
4 | 1 | 1 | 4
5 | 1 | 1 | 7
6 | 1 | 2 | 5
7 | 1 | 2 | 8
8 | 1 | 2 | 10
I've tried this, but then I realize it doesn't take the shops into consideration, it'll list all items that are not listed in reports, so if reports has an item for shop 2, it won't list it either...
SELECT Items.ID, Items.StockNbr, Items.Description, Items.GroupID, Reports.YearID, Reports.ShopID
FROM Reports
RIGHT JOIN Items ON Reports.ItemID = Items.ID
WHERE (((Items.GroupID)=1) AND ((Reports.UnitID) Is Null))
ORDER BY Items.StockNbr;
Thank you!
I think you're looking for an anti-join. There are several ways to do this. Here's one using not in.
select i.* from items i
where i.GroupId = 1
and i.ID NOT IN (
select ItemID from reports r
where r.ShopID = 1
and r.YearID = 2014
)
If the table Reports does not reference Items.ID then there is no available relationship ShopID or YearID
select *
from items
left join reports on items.id = reports.itemid
where reports.itemid IS NULL
I have two tables from a site similar to SO: one with posts, and one with up/down votes for each post. I would like to select all votes cast on the day that a post was modified.
My tables layout is as seen below:
Posts:
-----------------------------------------------
| post_id | post_author | modification_date |
-----------------------------------------------
| 0 | David | 2012-02-25 05:37:34 |
| 1 | David | 2012-02-20 10:13:24 |
| 2 | Matt | 2012-03-27 09:34:33 |
| 3 | Peter | 2012-04-11 19:56:17 |
| ... | ... | ... |
-----------------------------------------------
Votes (each vote is only counted at the end of the day for anonymity):
-------------------------------------------
| vote_id | post_id | vote_date |
-------------------------------------------
| 0 | 0 | 2012-01-13 00:00:00 |
| 1 | 0 | 2012-02-26 00:00:00 |
| 2 | 0 | 2012-02-26 00:00:00 |
| 3 | 0 | 2012-04-12 00:00:00 |
| 4 | 1 | 2012-02-21 00:00:00 |
| ... | ... | ... |
-------------------------------------------
What I want to achieve:
-----------------------------------
| post_id | post_author | vote_id |
-----------------------------------
| 0 | David | 1 |
| 0 | David | 2 |
| 1 | David | 4 |
| ... | ... | ... |
-----------------------------------
I have been able to write the following, but it selects all votes on the day before the post modification, not on the same day (so, in this example, an empty table):
SELECT Posts.post_id, Posts.post_author, Votes.vote_id
FROM Posts
LEFT JOIN Votes ON Posts.post_id = Votes.post_id
WHERE CAST(Posts.modification_date AS DATE) = Votes.vote_date;
How can I fix it so the WHERE clause takes the day before Votes.vote_date? Or, if not possible, is there another way?
Depending on which type of database you are using (SQL, Oracle ect..);To take the Previous days votes you can usually just subtract 1 from the date and it will subtract exactly 1 day:
Where Cast(Posts.modification_date - 1 as Date) = Votes.vote_date
or if modification_date is already in date format just:
Where Posts.modification_date - 1 = Votes.vote_date
If you have a site similar to Stack Overflow, then perhaps you also use SQL Server:
SELECT p.post_id, p.post_author, v.vote_id
FROM Posts p LEFT JOIN
Votes v
ON p.post_id = v.post_id
WHERE CAST(DATEDIFF(day, -1, p.modification_date) AS DATE) = v.vote_date;
Different databases have different ways of subtracting one day. If this doesn't work, then your database has something similar.
I found another solution, which is to add a day to Posts.modification_date:
...
WHERE CAST(CEILING(CAST(p.modification_date AS FLOAT)) AS datetime) = v.vote_date
I will first say that the table structure is (unfortunately) set.
My goal is to select several max() from a query. Lets say I have the following tables
jobReferenceTable jobList
jobID | jobName | jobDepartment | listID | jobID |
_______|__________|_______________| _______|_________|
1 | dishes | cleaning | 1 | 1 |
2 |vacumming | cleaning | 2 | 5 |
3 | mopping | cleaning | 3 | 2 |
4 |countMoney| admin | 4 | 4 |
5 | hirePpl | admin | 5 | 1 |
6 | 2 |
7 | 3 |
8 | 3 |
9 | 1 |
10 | 5 |
Somehow, I would like to have a query that selects the jobID's from cleaning, and then shows the most recent jobList ID's for each job. I started a query below, and below that are what I'm hoping to get as results
query
SELECT jrt.jobName, jrt.jobDepartment
FROM jobReferenceTable
WHERE jobDepartment = 'cleaning'
JOIN jobList jl ON jr.jobID = jl.jobID
results
jobName | jobDepartment | listID |
________|_______________|________|
1 | cleaning | 9 |
2 | cleaning | 6 |
3 | cleaning | 8 |
Try this;
SELECT jrt.jobName, jrt.jobDepartment, MAX(jl.listID)
FROM jobReferenceTable AS jrt INNER JOIN jobList AS jl ON jrt.jobID = jl.jobID
WHERE jrt.jobDepartment = 'cleaning'
GROUP BY jrt.jobName, jrt.jobDepartment
So far as I can see, you need only the one MAX() - the listID.
MAX() is an aggregate function, meaning that the rest of your result set must then be 'grouped'.
An example is the easiest way to explain what I'm looking to do:
GIVEN:
~move~
id | from | to
--------------
1 | 1 | 2
2 | 1 | 2
3 | 2 | 3
4 | 3 | 1
~locations~
id | name
---------
1 | home
2 | work
3 | out
How can I get:
id | from | to
----------------
1 | home | work
2 | home | work
3 | work | out
4 | out | home
That is, the human-readable name for both the from and to columns.
Select
Move.ID,
[From] = FromLocation.Name,
[To] = ToLocation.Name
From
Move
Inner Join Location As FromLocation On Move.[From] = FromLocation.ID
Inner Join Location As ToLocation On Move.[To] = ToLocation.ID