Master table contains ID and PersonName.
Course table contains ID, CourseName.
Detail table contains ID, MasterID, CourseID, StartDate,EndDate
I want to create report that shows list of persons (PersonName) and the only last course they took (so every person is listed only once):
PersonName - CourseName - StartDate - EndDate
select m.PersonName, c.CourseName
from Master m
join Detail d on d.MasterID = m.ID
join Course c on c.ID = d.CourseID
where d.StartDate = (select max(d2.StartDate)
from Detail d2
where d2.MasterID = m.ID
)
Select personname,coursename from details
inner join course on course.id = details.courseid
inner join master on master.id = details.masterid
inner join (select max(startdate) , courseid,masterid
from details group by masterid,courseid ) as tb1
on tb1.courseid = details.courseid and tb1.masterid = details.masterid
Related
I have the following query. This query allows me to produce a list of children and their familymember contacts (contactpupilID).
select s.studentnr,pc.pupilid, pc.contactpupilid, p2.mainmail
from student s
join pupil p on p.id = s.pupilid
join pupilcontact pc on pc.pupilid = p.id
join pupil p2 on p2.id = pc.contactpupilid
where CURRENT_DATE between pc.validfrom and pc.validuntil
order by pc.pupilid
Each child can have 0 to 3 familycontacts (0 because no contact has been added during registration).
Each familycontact (contactpupilid) has an email field. However there are cases where all familycontacts have an email or 1 of them or none of them.
My list needs to select a child with a familycontact(contactpupilid) that has an email. The familycontact that is selected should be the one that has an email.
If none of the familycontacts have an email then it should select the 1st familycontact by default.
This is how it needs to look like
How would I complete this task?
I don't know what you mean by "first record" because SQL tables are unordered. I can assume you mean the one with the smallest contactpupilid.
What you have described is what distinct on does:
select distinct on (s.studentnr) s.studentnr, pc.pupilid, pc.contactpupilid, p2.mainmail
from student s join
pupil p
on p.id = s.pupilid join
pupilcontact pc
on pc.pupilid = p.id join
pupil p2
on p2.id = pc.contactpupilid
where CURRENT_DATE between pc.validfrom and pc.validuntil
order by s.studentnr, (p2.mainmail is not null) desc;
Use ROW_NUMBER() window function in your query to rank the rows that contain an email first:
with cte as (
select s.studentnr, pc.pupilid, pc.contactpupilid, p2.mainmail,
row_number() over (partition by s.studentnr order by p2.mainmail is not null desc, pc.contactpupilid) rn
from student s
join pupil p on p.id = s.pupilid
join pupilcontact pc on pc.pupilid = p.id
join pupil p2 on p2.id = pc.contactpupilid
where CURRENT_DATE between pc.validfrom and pc.validuntil
)
select studentnr, pupilid, contactpupilid, mainmail
from cte
where rn = 1
order by pupilid;
You can do it with CTE like this
with temp as (
select s.studentnr,pc.pupilid, pc.contactpupilid, p2.mainmail,row_number() over (partition by pupilid order by pupilid) as row_number
from student s
join pupil p on p.id = s.pupilid
join pupilcontact pc on pc.pupilid = p.id
join pupil p2 on p2.id = pc.contactpupilid
where CURRENT_DATE between pc.validfrom and pc.validuntil
order by pc.pupilid
)
select *
from temp
where row_number = 1
I have two tables in Oracle DB
Person (
id
)
Bill (
id,
date,
amount,
person_id
)
I need to get person and amount from last bill if exist.
I trying to do it this way
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN Bill b
ON b.person_id = p.id AND b.date = (SELECT MAX(date) FROM Bill WHERE person_id = 1)
WHERE p.id = 1;
But this query works only with INNER JOIN. In case of LEFT JOIN it throws ORA-01799 a column may not be outer-joined to a subquery
How can I get amoun from the last bill using left join?
Please try the below avoiding sub query to be outer joined
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN(select * from Bill where date =
(SELECT MAX(date) FROM Bill b1 WHERE person_id = 1)) b ON b.person_id = p.id
WHERE p.id = 1;
What you are looking for is a way to tell in bills, for each person, what is the latest record, and that one is the one to join with. One way is to use row_number:
select * from person p
left join (select b.*,
row_number() over (partition by person_id order by date desc) as seq_num
from bills b) b
on p.id = b.person_id
and seq_num = 1
You cannot have a subquery inside an ON statement.
Instead you need to convert your LEFT JOIN statement into a whole subquery.
Not tested but this should work.
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN (
SELECT id FROM Bill
WHERE person_id = p.id
AND date = (SELECT date FROM Bill WHERE person_id = 1)) b
WHERE p.id = 1;
I'm not quite sure why you would want to filter for the date though.
Simply filtering for the person_id should do the trick
you should join Person and Bill to the result for max date in bill related to person_id
select Person.id, bill.amount
from Person
left join bill on bill.person_id = person.id
left join (
select person_id, max(date) as max_date
from bill
group by person_id ) t on t.person_id = Person.id and b.date = t.max_date
Hey you can do like this
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN Bill b
ON b.person_id = p.id AND b.date = (SELECT max(date) FROM Bill WHERE person_id = 1)
WHERE p.id = 1
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN Bill b
ON b.person_id = p.id
WHERE (SELECT max(date) FROM bill AS sb WHERE sb.person_id=p.id LIMIT 1)=b.date;
SELECT
p.id,
c.amount
FROM Person p
LEFT JOIN (select b.person_id as personid,b.amount as amount from Bill b where b.date1= (select max(date1) from Bill where person_id=1)) c
ON c.personid = p.id
WHERE p.id = 1;
try this
select * from person p
left join (select MAX(id) KEEP (DENSE_RANK FIRST ORDER BY date DESC)
from bills b) b
on p.id = b.person_id
I use GREATEST() function in join condition:
SELECT
p.id,
b.amount
FROM Person p
LEFT JOIN Bill b
ON b.person_id = p.id
AND b.date = GREATEST(b.date)
WHERE p.id = 1
This allows you to grab the whole row if necessary and grab the top x rows
SELECT p.id
,b.amount
FROM person p
LEFT JOIN
(
SELECT * FROM
(
SELECT date
,ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY date DESC) AS row_num
FROM bill
)
WHERE row_num = 1
) b ON p.id = b.person_id
WHERE p.id = 1
;
In my database i have following tables:
Person (
id,
name,
agentId
)
Agent (
id,
title
)
Agency (
id,
name
)
AgentAgency (
id,
agentId,
agencyId
)
I need query that will get all info about Person -> Agents with extra attribute numberOfAgencies that will show number of agencies of each agent, AND i need to show one more attribute agencyName that will show me name of first or only agency that user have (i need it in case agent have only 1 agency).
I tried something like this but without any success.
SELECT *, COUNT (aa.agentId) as numberOfAgencies
FROM agentAgencies as aa
LEFT JOIN agent as a ON a.id = aa.agentId
LEFT JOIN agency as ag ON aa.agencyId= ag.id
LEFT JOIN person as p ON p.id = ag.personId
GROUP BY ag.id, aa.id, p.id, a.id
For example i expect response like this:
PersonName John, AgencyName Cool Agency, numberOfAgencies 4
SELECT
MAX(p.Name) PersonName,
count(a.id) NoOfAgencies,
MAX(a.name) AgencyName
FROM persons p
LEFT OUTER JOIN agent g ON g.Id=p.agentId
LEFT OUTER JOIN AgentAgency aa ON aa.agentId = g.Id
LEFT OUTER JOIN Agency a on a.id = aa.agencyId
GROUP BY a.Id
This one is confusing me?
There are three tables. Appointments(Appointment_ID, Physician_ID and Person_ID) , Physician(Physician_ID) and a Person(Person_ID and Physician_ID).
This is what I have so far :
SELECT DISTINCT Appointment_date_time FROM Appointment
INNER JOIN Person
ON Appointment.Person_ID = Person.Person_ID
INNER JOIN Physician
ON Physician.Physician_ID = Person.Physician_ID
HAVING COUNT(*) < 1
There are three tables. Appointments(Appointment_ID, Physician_ID and Person_ID) , Physician(Physician_ID) and a Person(Person_ID and Physician_ID).
select *
from Appointments a
inner join Person p
on a.Person_ID = p.Person_ID
inner join Physician ph
on a.Physician_ID = ph.Physician_ID
I've always done this back asswards in PHP or ASAP, so I figure it's time to actually learn the proper way to do it in SQL. I have the following 4 tables in a database:
Category (Fields: CategoryNumber, Desc) (small table with 15 rows)
Media (Fields: MediaID, Desc, CategoryNumber, etc) (huge table with 15,000 rows)
Sales (Fields: Date, MediaID, EmployeeID etc) (huge table with 100,000 rows)
Employees (Fields: EmployeeID, Name, etc) (small table with only 20 rows)
Category only links to Media
Media has links to both Category and Sales.
Sales links to both the Media and Employee
Employee only links to Sales
What I would like to do is to write a query which tells me what categories a given employee has never sold any media in.
I can write a simple query that looks for unmatched data between 2 tables, but I have no clue how to do it when I'm dealing with 4 tables.
Thanks for your time and help!
Here's my suggestion:
select *
from Category c
where not exists (
select *
from Employee e
inner join Sales s on s.EmployeeId = e.EmployeeId
inner join Media m on m.MediaID = s.MediaID
where e.Name = 'Ryan' and m.CategoryNumber = c.CategoryNumber
)
To query all employes with the categories in which they didn't sell anything:
select e.EmployeeName, c.CategoryNumber
from Category c
cross join Employee e
where not exists (
select *
from Sales s
inner join Media m on m.MediaID = s.MediaID
where c.categoryNumber = m.CategoryNumber
and s.EmployeeId = e.EmployeeId
)
SELECT c.CategoryNumber, c.Desc
FROM Category c
WHERE NOT EXISTS
(
SELECT *
FROM Employees e
INNER JOIN Sales s on s.EmployeeID = e.EmployeeID
INNER JOIN Media m on m.MediaID = s.MediaID
WHERE e.Name = "Ryan"
AND m.CategoryNumber = c.CategoryNumber
)
MS Access evidently needs a lot of parentheses (thanks, Ryan!):
select *
from Category c
where not exists
( select *
from ( Employee e
inner join Sales s on (s.EmployeeId = e.EmployeeId))
inner join Media m on (m.MediaID = s.MediaID)
where (e.Name = 'Ryan' and m.CategoryNumber = c.CategoryNumber) )
select c.desc
from category
left outer join (select s.employeeid,m.categorynumber
from sales s
inner join media m on s.mediaid=m.mediaid
inner join employee e on e.employeeid=s.employeeid
where e.name = 'JOE'
group by employeeid,categorynumber) t on t.categorynumber=c.categorynumber
where s.employeeid is null
Modified Answer based on the solution provided by Carl in Access SQL Syntax:
select *
from Category c
where not exists (
select *
from (Employee e
inner join Sales s on (s.EmployeeId = e.EmployeeId))
inner join Media m on (m.MediaID = s.MediaID)
where (e.Name = 'Ryan' and m.CategoryNumber = c.CategoryNumber)
)