Short context:
I would like to show a list of all companies except if they are in the sector 'defense' or 'government' and their individual total spent on training classes. Only the companies that have this total amount above 1000 must be shown.
So I wrote the following query:
SELECT NAME, ADDRESS, ZIP_CODE, CITY, SUM(FEE-PROMOTION) AS "Total spent on training at REX"
FROM COMPANY INNER JOIN PERSON ON (COMPANY_NUMBER = EMPLOYER) INNER JOIN ENROLLMENT ON (PERSON_ID = STUDENT)
WHERE SECTOR_CODE NOT IN (SELECT CODE
FROM SECTOR
WHERE DESCRIPTION = 'Government' OR DESCRIPTION = 'Defense')
GROUP BY NAME, ADDRESS, ZIP_CODE, CITY
HAVING SUM(FEE-PROMOTION) > 1000
ORDER BY SUM(FEE-PROMOTION) DESC
Now what I actually need is, instead of defining every single column in the COMPANY table, I would like to show ALL columns of the COMPANY table using *.
SELECT * (all tables from COMPANY here), SUM(FEE-PROMOTION) AS "Total spent on training at REX"
FROM COMPANY INNER JOIN PERSON ON (COMPANY_NUMBER = EMPLOYER) INNER JOIN ENROLLMENT ON (PERSON_ID = STUDENT)
WHERE SECTOR_CODE NOT IN (SELECT CODE
FROM SECTOR
WHERE DESCRIPTION = 'Government' OR DESCRIPTION = 'Defense')
GROUP BY * (How to fix it here?)
HAVING SUM(FEE-PROMOTION) > 1000
ORDER BY SUM(FEE-PROMOTION) DESC
I could define every single column from COMPANY in the SELECT and that solution will do the job (as in the first example), but how can I make the query shorter using "SELECT * from the table COMPANY"?
The key idea is to summarize in the subquery to get the total spend for the company. This allows you to remove the aggregation from the outer query:
select c.*, pe.total_spend
from company c join
sector s
on c.sector_code = s.code left join
(select p.employer, sum(e.fee - e.promotion) as training_spend
from person p join
enrollment e
on p.person_id = e.student
group by p.employer
) pe
on pe.employer = c.company_number
where s.sector not in ('Government', 'Defense') and
pe.total_spend > 1000
Related
database structure
Professor
prof_id number
name string
salary number
building string
Course
name string
prof_id number
room_number number
start_time number
end_time number
Room
room_number number
capacity number
building string
Professors with at least 1 math course:
select distinct Professor.name, count(Course.name) AS numberOfMathCourses
from Course
LEFT JOIN Room
ON Course.Room_id = Room.Room.id
INNER JOIN Professor
ON Professor.id = Course.id
where Course.name = 'math'
group by Professor.name
having numberOfMathCourses > 0
Professors with less than 3 courses :
select distinct Professor.name, count(Course.name) AS numberOfCourses
from Course
LEFT JOIN Room
ON Course.Room_id = Room.Room.id
INNER JOIN Professor
ON Professor.id = Course.id
group by Professor.name
having numberOfCourses < 3
how would do I create a Query that has both of these conditions ? more than one math course course and less than 3 courses.
I tried sub-queries but I wasn't able to make it work. I will try to look into it more. Thanks for the help.
select *
from Professor p
where
(select count(*) from Course c where p.prof_id = c.prof_id and c.name = 'math') > 0
and (select count(*) from Course c where p.prof_id = c.prof_id) < 3
For questions below, use the following schema definition.
restaurant(rid, name, phone, street, city, state, zip)
customer(cid, fname, lname, phone, street, city, state, zip)
carrier(crid, fname, lname, lp)
delivery(did, rid, cid, tim, size, weight)
pickup(did, tim, crid)
dropoff(did, tim, crid)
It's a schema for a food delivery business that employs food carriers (carrier table).
Customers (customer table) order food from restaurants (restaurant table).
The restaurants order a delivery (delivery table); to deliver food from restaurant to customer.
The pickup table records when carrier picks up food at restaurant.
The dropoff table records when carrier drops off food at customer.
1.Find customers who have less than 5 deliveries.
a. select cid,count()
from delivery
group by cid
having count() < 5;
b. select a.cid,count()
from customer a
inner join delivery b
using(cid)
group by a.cid
having count() < 5;
c. select a.cid,count()
from customer a
left outer join delivery b
on a.cid=b.cid
group by a.cid
having count() < 5;
d. select cid,sum(case when b.cid is not null then 1 else 0 end)
from customer a
left outer join delivery b
using (cid)
group by cid
having sum(case when b.cid is not null then 1 else 0 end) < 5;
e. (write your own answer)
No, they are not correct. They miss customers who have had no deliveries.
The last is the best of a bunch of not so good queries. A better version would be:
select c.cid, count(d.cid)
from customer c left outer join
delivery d
on c.cid = d.cid
group by c.cid
having count(d.cid) < 5;
The sum(case) is over kill. And Postgres even offers a better solution than that!
count(*) filter (where d.cid is not null)
But count(d.cid) is still more concise.
Also note the use of meaningful table aliases. Don't get into the habit of using arbitrary letters for tables. That just makes queries hard to understand.
I have a table of hospitals details, department details linked to it, types of workers (the staff) in different tables, and their salary information.
I want to extract the following for each hospital: the average and the sum of the salaries, the number of nurses, the number of research doctors and the number of beds in all the departments of a specific hospital.
I built this view of all the workers salary information:
CREATE VIEW workers AS
SELECT hospcod, docsal as sal, 'treatdoc' as typework
FROM doc NATURAL JOIN treatdoc NATURAL JOIN dept
UNION
SELECT hospcod, nursal, 'nurse'
FROM nurse NATURAL JOIN dept
UNION
SELECT hospcod, docsal, 'rsrchdoc'
FROM doc NATURAL JOIN rsrchdoc NATURAL JOIN lab;
the departments and the labs have the hospital code column to correlate a worker information to a specific hospital.
so I have one sceme for all the staff with their rules workers(hospital_code, salary, type_of_worker)
here is the query I'm trying to build:
SELECT hospname, sum(workers.sal), avg(workers.sal), count(dept.numbed),
(SELECT count(typework) from workers where typework = 'nurse') nurse_num,
(SELECT count(typework) from workers where typework = 'rsrchdoc') rsrchdoc_num
FROM hosp NATURAL JOIN dept NATURAL JOIN workers
GROUP BY hospname;
I want to count for each hospital, the number of nurses and the number of research doctors
but it should be correlated somehow to the different hospitals (in the above it gives me the same number of nurses / rsrchdocs for each hospital) , there should be columns that is grouped by hospnames and should get all the tuples like the salary info (avg, sum), as I got properly, but the workers information should be grouped HAVING typework = 'nurse' for the nurse_num, and for the column rsrchdoc_numit should be HAVING typework = 'rsrchdoc_num'
does someone have an idea how can I combine thouse columns in one query?
thank you!
There is an error in your query, I will try to explain.
When you do:
(SELECT count(typework) from workers where typework = 'nurse') nurse_num,
You are getting a constant, that is not affected by the "group by" you are doing after.
What you have to do is a JOIN (like you did in the view) and link the nurse and the rsrchdoc to an specific hospital.
I will give an example is pseudo code
SELECT hosp_name, sum(nurse.salary) , avg(nurse.salary)
FROM hosp
JOIN nurse ON nurse.hosp_name = hosp.hosp_name
GROUP BY hosp.hosp_name
This query will give you 1 row for each nurse in each hospital (assuming that a nurse may work in more than one hospital).
Then you have to do the same thing also for doctors, in a different operation.
SELECT hosp_name, sum(doctors.salary) , avg(doctors.salary)
FROM hosp
JOIN doctors ON doctors.hosp_name = hosp.hosp_name
GROUP BY hosp.hosp_name
And finally you will have to join both ( you may perform the sum first to make it more readable.
SELECT hosp_name, sum_sal_doc, avg_sal_doc, sum_nur_doc, avg_nur_doc
FROM hosp
LEFT JOIN ( SELECT doctors.hosp_name, sum(doctors.salary) as sum_sal_doc, avg(doctors.salary) as avg_sal_doc
FROM doctors
GROUP BY doctors.hosp_name
) t1 ON t1.hosp_name = hosp.hosp_name
LEFT JOIN ( SELECT nurses.hosp_name, sum(nurses.salary) as sum_nur_doc, avg(nurses.salary) as avg_nur_doc
FROM nurses
GROUP BY nurses.hosp_name
) t2 ON t2.hosp_name = hosp.hosp_name
There must be 1 to many relationship between hosp --> dept and hosp --> workers so if you join these 3 tables then you will definitely find the duplicates for dept and workers so you must have to create sub-query for one of the dept or workers to fetch single grouped record group by hospital as follows:
SELECT h.hospname,
sum(w.sal) total_all_worker_sal,
avg(w.sal) avg_all_workers_sal,
d.numbed,
count(case when w.typework = 'nurse' then 1 end) nurse_num,
count(case when w.typework = 'rsrchdoc' then 1 end) rsrchdoc_num
FROM hosp h
JOIN (select hospital_code , sum(numbed) numbed
-- used SUM as numbed must be number of bed in department
-- COUNT will give you only number of department if you use count(d.numbed)
from dept
group by hospital_code) d ON h.hospital_code = d.hospital_code
JOIN workers w ON h.hospital_code = d.hospital_code
GROUP BY h.hospital_code , h.hospname, d.numbed;
-- used h.hospital_code to separate the records if two hospitals have same name
I need to find the sum of all the rental days of a car dealership (including
period_begin and period_end, not unique) for all cars of that department.Divided by the total number of different (unique) employees that department ever had.
I have 5 tables
Department(PK departmentnr, name, FK postcode, FK place_name)
Employee(PK employeenr, FK email)
Contract(PK periode_begin, PK periode_end, FK departmentnr, FK employeenr)
registerform (,PK periode_end,PK,periode_end,FKemail,FK,
Fk numberplate,periode_end,periode_begin)
car(PK numberplate,FK departmentnr,FK Brand,FK model)
when I go step by step
part 1
The total employees per department
select departmentnr,Count(employeenr)FROM contract
group by departmentnr
part 2
the amount of days the cars were hired
SELECT DISTINCT departmentnr,
Sum((( Date(periode_end) - Date(periode_begin) + 1 ))) AS
average
FROM registerform r
INNER JOIN car w using(numberplate)
GROUP BY departmentnr
I get the correct ouput but when I try to get these 2 together
SELECT distinct departmentnr,
(
sum(((date(r.periode_end) - date(r.periode_begin) + 1))) / (
select
count(employeenr))
)
as average
from
registerform r
inner join
car w using(numberplate)
inner join
contract using(departmentnr)
inner join
employee using(employeenr)
group by
departmentnr
then my output gets absurd.
How can I fix this and is there a way to make the code more efficient.
Aggregated before you JOIN. So, one method is:
SELECT c.departmentnr, co.num_employees,
Sum( Date(r.periode_end) - Date(r.periode_begin) + 1 ) AS average
FROM registerform r JOIN
car c
USING (numberplate) LEFT JOIN
(SELECT co.departmentnr, Count(*) as num_employees
FROM contract co
GROUP BY co.departmentnr
) co
ON co.departmentnr = c.departmentnr
GROUP BY c.departmentnr, co.num_employees;
I have 3 tables:
Person (with a column PersonKey)
Telephone (with columns Tel_NumberKey, Tel_Number, Tel_NumberType e.g. 1=home, 2=mobile)
xref_Person+Telephone (columns PersonKey, Tel_NumberKey, CreatedDate, ModifiedDate)
I'm looking to get the most recent (e.g. the highest Tel_NumberKey) from the xref_Person+Telephone for each Person and use that Tel_NumberKey to get the actual Tel_Number from the Telephone table.
The problem I am having is that I keep getting duplicates for the same Tel_NumberKey. I also need to be sure I get both the home and mobile from the Telephone table, which I've been looking to do via 2 individual joins for each Tel_NumberType - again getting duplicates.
Been trying the following but to no avail:
-- For HOME
SELECT
p.PersonKey, pn.Phone_Number, pn.Tel_NumberKey
FROM
Persons AS p
INNER JOIN
xref_Person+Telephone AS x ON p.PersonKey = x.PersonKey
INNER JOIN
Telephone AS pn ON x.Tel_NumberKey = pn.Tel_NumberKey
WHERE
pn.Tel_NumberType = 1 -- e.g. Home phone number
AND pn.Tel_NumberKey = (SELECT MAX(pn1.Tel_NumberKey) AS Tel_NumberKey
FROM Person AS p1
INNER JOIN xref_Person+Telephone AS x1 ON p1.PersonKey = x1.PersonKey
INNER JOIN Telephone AS pn1 ON x1.Tel_NumberKey = pn1.Tel_NumberKey
WHERE pn1.Tel_NumberType = 1
AND p1.PersonKey = p.PersonKey
AND pn1.Tel_Number = pn.Tel_Number)
ORDER BY
p.PersonKey
And have been looking over the following links but again keep getting duplicates.
SQL select max(date) and corresponding value
How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?
SQL Server: SELECT only the rows with MAX(DATE)
Am sure this must be possible but been at this a couple of days and can't believe its that difficult to get the most recent / highest value when referencing 3 tables. Any help greatly appreciated.
select *
from
( SELECT p.PersonKey, pn.Phone_Number, pn.Tel_NumberKey
, row_number() over (partition by p.PersonKey, pn.Phone_Number order by pn.Tel_NumberKey desc) rn
FROM
Persons AS p
INNER JOIN
xref_Person+Telephone AS x ON p.PersonKey = x.PersonKey
INNER JOIN
Telephone AS pn ON x.Tel_NumberKey = pn.Tel_NumberKey
WHERE
pn.Tel_NumberType = 1
) tt
where tt.rn = 1
ORDER BY
tt.PersonKey
you have to use max() function and then you have to order by rownum in descending order like.
select f.empno
from(select max(empno) empno from emp e
group by rownum)f
order by rownum desc
It will give you all employees having highest employee number to lowest employee number. Now implement it with your case then let me know.