I have a timetable editor on a web page and I need to select TIMETABLE by using CLASS ID and by all users which are in that class by USER.CLASS ID = CLASS ID and from that users get GROUPs which have GROUP ID and GET ALL TIMETABLES with GROUP ID. Sorry for my explaining knowledge.
user is linked to class by cid.
userGroup is just uid and gid.
timetable has both cid and gid. When first is null second is given.
I've tried code below, and many combinations of all the JOINs which I can't seem to get working
SELECT DISTINCT
`timetable`.*,
`group`.name AS groupName,
`class`.name AS className
FROM
`timetable`,
`user`,
`userGroup`
LEFT OUTER JOIN `group` ON `userGroup`.gid = `group`.gid
LEFT OUTER JOIN `class` ON `class`.cid = '1'
WHERE
`user`.cid = 1 AND `userGroup`.uid = `user`.uid AND(
`timetable`.gid = `group`.gid OR `timetable`.cid = '1'
)
I expected output with 3 timetables. 1 from the class and 2 from different groups which are connected to users which are connected by class. I also wanted names which one is from GROUP and one from CLASS by respected ids i.e (gid, cid). Is there even way to get NULL on the className if cid is null?
I followed suggestion by #spencer7593 by using only "new-syntax" JOIN.
SELECT DISTINCT
`timetable`.*,
`group`.name AS groupName,
`class`.name AS className
FROM
`timetable`
JOIN `user` ON `user`.cid = 1
JOIN `userGroup` ON `userGroup`.uid = `user`.uid
LEFT JOIN `group` ON `userGroup`.gid = `group`.gid AND `timetable`.cid IS null
LEFT JOIN `class` ON `class`.cid = '1' AND `timetable`.gid IS null
WHERE
`timetable`.gid = `userGroup`.gid OR `timetable`.cid = '1'
Related
Have tables: person,person_ip
Both tables have pid column as a primary key, in table person there is column state_id, in table person_ip there is column ip.
Want to discover if specified IP address is assigned to person with state_id is not equal to 2. But always got result 1, even if state_id is 0, 1 or 2. Always got 0 only if ip address is not listed at all. What am I doing wrong?
SELECT EXISTS (
SELECT person_ip.PID
FROM person_ip,person
WHERE person.PID=person_ip.PID
AND person.state_id NOT IN (2)
AND person_ip.ip='10.11.12.13'
)
this seems like a simple join.. unless i'm missing something
select person.*
from person
inner join person_ip
on person.pid = person_ip.pid
where person.state_id <> 2
and person_ip.ip_address = '10.0.0.1'
If you want to exclude the ip_address if it has been assigned to any user with state = 2, even if it has also been assigned to a user without state = 2, then try:
select max(i)
from (
select *
from (
select 1 as i
from dual
where not exists (
select 1
from person p
inner join person_ip pi
on p.pid = pi.pid
where p.state_id = 2
and pi.ip_address = '10.0.0.1'
)
) q
union
select 0
) qq
(dual is a system table that can be used as a sort of stub table)
here's a fiddle showing both versions
update after some actual sleep
Okay, so the above query is a little.. out there. Back in the real world, this one is probably more appropriate:
select count(case when p1.state_id = 2 then 1 end)
from person p1
inner join person_ip pi1
on p1.pid = pi1.pid
where pi1.ip_address = '10.0.0.1'
group by pi1.ip_address;
This will return 1 or more if your ip_address has been used by someone with a state_id of 2, and 0 if it has never been used by someone with a state_id of 2.
It will return nothing if the ip has never been used.
this fiddle has all three of the above queries.
SELECT IF(COUNT(*)>0,1,0)
FROM person
INNER JOIN person_ip
ON person.pid = person_ip.pid
AND person_ip.ip_address = '10.0.0.1'
WHERE person.state_id <> 2
I have a query as follows:
SELECT
staff_names.staff_ID AS sid
staff_names.name AS name,
staff_names.rec_type AS rec_type,
prod_staff.specialized AS specialized,
compspec.name AS compspec_name
FROM staff_names JOIN prod_staff USING (staff_ID)
LEFT JOIN (prod_staff_compspec JOIN company_list USING (comp_ID)) compspec
USING (prod_ID, staff_ID, role_ID)
WHERE prod_staff.role_ID = 2
AND prod_staff.prod_ID = 27
AND prod_staff.asst = 'n'
AND episode IS NOT NULL
ORDER BY name
Running this as-is says there's an error near the 'compspec' alias. Removing that and changing 'compspec' to 'company_list' in the SELECT clause returns no rows, even though it should return 1 with the given values. The left join seems to be the problem, but I don't how it should be formatted.
The prod_staff table has prod_ID, staff_ID and role_ID fields. prod_staff_compspec has these and a comp_ID field. prod_staff may or may not have a matching prod_staff_compspec row, but prod_staff_compspec always has a matching company_list row.
What I want to do is retrieve a list of all staff names associated with a given role_ID and prod_ID in the prod_staff table, as well as a company name from the company_list table, if a link to such exists in the prod_staff_compspec table (only a small minority have one).
Switched to ON to define the table relations. LEFT JOIN (prod_staff_compspec JOIN company_list USING (comp_ID)) compspec is switched to 2 left join.
select a.staff_id sid, a.name, a.rec_type, b.specialized, d.name compspec_name
from staff_names a
join prod_staff b on a.staff_id = b.staff_id
left join prod_staff_compspec c on b.prod_id = c.prod_id and b.staff_id = c.staff_id and b.role_id = c.role_id
left join company_list d on c.comp_id = d.comp_id
where b.role_id = 2 and b.prod_id = 27 and b.asst = 'n' and episode is not null
order by a.name;
I have the logic worked out, just not sure how to best write this query.
the logic is
we have a deal ID of 1
a deal is linked to multiple regions
a deal is linked to multiple interests
a user is linked to multiple regions
a user is linked to multiple interests
we want all users where....
the user is linked to the same region as a deal
userRegionLink url, dealRegionLink drl
url.regionId is in drl.regionId where drl.dealId = 1
the user is linked to the same interest as a deal
userInterestLink uil, dealInterestLink dil
uil.interestId is in dil.interestId where dil.dealId = 1
this would give us a list of the users
now we need to select distinct from the list so we only end up sending each user a single email
But I have no idea what the best way to write this query would be.
We are dealing with a few tables here
We have
users which has all the user Information in it userId and other columns not important
userInterestLink which has userId and interestId
dealInterestLink which has dealId and interestId
userRegionLink which has userId and regionId
dealRegionLink which has dealId and regionId
so what we are wanting in the end is all the user info which matches.
I take RC's answer and modify it
SELECT u.userId, uil.interestId, url.regionId FROM users u
JOIN userInterestLink uil ON (uil.userId = u.userId)
JOIN userRegionLink url ON (url.userId = u.userId)
WHERE interestId IN (
SELECT DISTINCT interestId FROM dealInterestLink WHERE dealId = 1
) AND regionId IN (
SELECT DISTINCT regionId FROM dealRegionLink WHERE dealId = 1
)
as there is no need for LEFT JOIN if I exclude the NULL rows afterwards.
A more "symmetric" version without subqueries and with USING would be
SELECT u.userId, uil.interestId, url.regionId FROM users u
JOIN userInterestLink uil USING (userId)
JOIN userRegionLink url USING (userId)
JOIN dealInterestLink dil USING (interestId)
JOIN dealRegionLink drl USING (regionId, dealId)
WHERE dealId = 1
Untested as well.
Something like:
SELECT u.userId, uil.interestId, url.regionId FROM users u
LEFT JOIN userInterestLink uil ON (uil.userId = u.userId)
LEFT JOIN userRegionLink url ON (url.userId = u.userId)
WHERE uil.interestId IS NOT NULL AND uil.interestId IN (
SELECT DISTINCT interestId FROM dealInterestLink WHERE dealId = 1
) AND url.regionId IS NOT NULL AND url.regionId IN (
SELECT DISTINCT regionId FROM dealRegionLink WHERE dealId = 1
)
? If result is OK, you can then SELECT DISTINCT u.userId FROM users u -- ...
(not tested)
SELECT `u`.*
FROM `users` AS `u`
JOIN `userRegionLink` `userReg` USING ( `userId` )
JOIN `userInterestLink` `userInt` USING ( `userId` )
JOIN `dealInterestLink` `dealInt` USING ( `interestId` )
JOIN `dealRegionLink` `dealReg` USING ( `regionId` )
JOIN `deal` `d` ON ( `dealInt`.`dealId` && `dealReg`.`dealId` && `d`.`dealId` = 1 )
GROUP BY `u`.`userId`
Tested locally using dummy data and presumed schema. Worked OK.
To begin with I have 4 tables I am dealing with.
I have a classes table that is a 1->N relationship with a sections table which also has a 1->N relationship with a lessons table.
So to put it in perpective:
Classes
Sections
Lessons
The last table is an activityLog, when the student accesses a lesson this is recorded using the following:
ActivityLog Row -> actorID (user ID), classID, sectionID, lessonID
I want to pull out the last 5 unique lessons the student has visited. I tried using both DISTINCT and GROUP BY without success.
The same records are being returned each time, not the latest classes that they have visited.
Using GROUP BY
SELECT activityLog.actorID, activityLog.activityDate,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
GROUP BY activityLog.lessonID
ORDER BY activityLog.activityDate DESC
LIMIT 5
Using DISTINCT
SELECT DISTINCT activityLog.actorID,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
ORDER BY activityLog.activityDate DESC
LIMIT 5
I cannot figure out why the latest records are not being displayed.
Based on your change, how does this suit you?
SELECT activityLog.actorID, activityLog.activityDate,
strClasses.classID, strClasses.className,
strSections.sectionID, strSections.sectionName,
strLessons.lessonID, strLessons.lessonName
FROM activityLog
LEFT JOIN strClasses ON strClasses.classID = activityLog.classID
LEFT JOIN strSections ON strSections.sectionID = activityLog.sectionID
LEFT JOIN strLessons ON strLessons.lessonID = activityLog.lessonID
WHERE activityLog.activityTypeID = 6 AND activityLog.actorID = 3
AND activityLog.activityDate = (SELECT MAX(activityDate) FROM activityLog AS lookup WHERE lessonID = activityLog.lessonID)
ORDER BY activityLog.activityDate DESC
LIMIT 5
Based on your description, I'm not sure why you're using LEFT JOIN, but I've left it in just in case.
Try group by like below
GROUP BY activityLog.classID,activityLog.sectionID,activityLog.lessonID
I think it will work, or just sent me create scripts for these I will create that query
Well, there's got to be a datetime in the ActivityLog I hope... so Try this:
Select s.Name, c.ClassName
From Students s
left Join On Classes c
On c.ClassId In
(Select Distinct ClassId From Classes
Where (Select Count(Distinct ClassId) From Classes ic
Join ActivityLog l On l.UserId = s.UserId
And l.ClassId = c.ClassId
Where classId = c.ClassId
And activityDateTime > l.activityDateTime)
< 5)
I have a rather complex-seeming query that will form the basis for an online classroom scheduling tool. My challenge is to develop a method to identify which classes a user is signed up for in the st_schedule table, then deduce from the overall table of classes, st_classes, which other classes are available that don't conflict with the user's current classes.
For example, if a user has an entry in st_schedule assigning them to a class from 8:00am to 9:00am, they would be ineligible for any class whose time fell between 8:00am and 9:00am. A class that ran 7:15am - 8:15am would make the user ineligible. I store the start times and end times of classes in the database separately for comparison purposes. It's important that this be as flexible as possible, so the concept of "blocking" times and assigning times to blocks is not a possibility.
Here are excerpts from the tables:
table st_classes (holds class information)
id
start_time
end_time
table st_schedule (holds schedule information)
id
user_id
class_id
I certainly could do this in a series of loops server-side, but I have to think that there's a MySQL method that can do this type of operation in one fell swoop.
You want to join the two tables together to represent the user's classes, and then find unregistered classes where the start time and end time do not fall between the start and end time of the user's classes.
Something like this. Completely off the cuff and untested:
SELECT
*
FROM
st_schedule s
INNER JOIN st_classes c ON c.id = s.class_id
INNER JOIN st_classes all_classes
ON all_classes.start_time NOT BETWEEN c.start_time AND c.end_time
AND all_classes.end_time NOT BETWEEN c.start_time AND c.end_time
WHERE
s.user_id = 1
Edit: Try #2
I only have a moment to look at this. I think I reversed the second join clauses. The all_classes alias represents the full list of classes, where the "c" alias represents the classes that the student is signed up for.
SELECT DISTINCT
all_classes.*
FROM
st_schedule s
INNER JOIN st_classes c ON c.id = s.class_id
INNER JOIN st_classes all_classes
ON c.start_time NOT BETWEEN all_classes.start_time AND all_classes.end_time
AND c.end_time NOT BETWEEN all_classes.start_time AND all_classes.end_time
WHERE
s.user_id = 1
This is using table variables in mssql but the sql selects should translate over to mysql
First the sample data
DECLARE #st_classes TABLE
(
ID INT NOT NULL,
Title VARCHAR(40) NOT NULL,
StartTime DATETIME NOT NULL,
EndTime DATETIME NOT NULL
)
DECLARE #st_schedule TABLE
(
ID INT NOT NULL,
UserID INT NOT NULL,
ClassID INT NOT NULL
)
INSERT INTO #st_classes (ID, Title, StartTime, EndTime)
SELECT 1,'Class1','08:00:00','09:30:00' UNION
SELECT 2,'Class2','09:30:00','11:30:00' UNION
SELECT 3,'Class3','11:30:00','16:00:00' UNION
SELECT 4,'Class4','16:00:00','17:30:00' UNION
SELECT 5,'Class5','09:00:00','11:45:00' UNION
SELECT 6,'Class6','07:00:00','18:00:00'
INSERT INTO #st_schedule(ID, UserID, ClassID)
SELECT 1,1,1 UNION
SELECT 2,1,2 UNION
SELECT 3,2,6
Next a bit of sql to confirm the tables join OK (selecting scheduled courses for user with an ID of 1) - Returns class 1 and 2
SELECT *
FROM #st_schedule AS S INNER JOIN
#st_classes AS C ON S.ClassID = C.ID
WHERE S.UserID = 1
Now we need to select all the ID of the courses where they overlap time wise with the users scheduled ones (including the scheduled ones) - Returns 1,2,5,6
SELECT AC.ID
FROM #st_classes AS AC
INNER JOIN ( SELECT C.StartTime,
C.EndTime
FROM #st_schedule AS S
INNER JOIN #st_classes AS C ON S.ClassID = C.ID
WHERE S.UserID = 1
) AS UC ON ( AC.StartTime < DATEADD(ss, -1, UC.EndTime)
AND DATEADD(ss, -1, UC.EndTime) > UC.StartTime
)
GROUP BY AC.ID
Now we need to select all courses where the Course ID is not in our list of overlapping course IDs. - Returns course 3 and 4
SELECT *
FROM #st_classes
WHERE ID NOT IN (
SELECT AC.ID
FROM #st_classes AS AC
INNER JOIN ( SELECT C.StartTime,
C.EndTime
FROM #st_schedule AS S
INNER JOIN #st_classes AS C ON S.ClassID = C.ID
WHERE S.UserID = 1
) AS UC ON ( AC.StartTime < DATEADD(ss, -1, UC.EndTime)
AND DATEADD(ss, -1, UC.EndTime) > UC.StartTime
)
GROUP BY AC.ID )
Change the user ID filter to 2 and you should not get any returned as the course assigned to that user overlaps all courses.