I need to calculate the total cost for the job_id including the wages and cost of fittings.
I only manage to calculate one at time. I need to sum both wages and fittings cost by job_id.
staff_on_job Table(FK: staff_id,job_id)
fittings Table
job_fittings Table(FK: job_id,fitting_name)
Calculate the wages on per job_id
select job_id ,sum(hours*30)from staffs_on_job group by job_id;
Output
calculate the total fitting cost on per job_id
select jf.job_id ,sum(f.cost)
from jobs_fittings jf left OUTER JOIN fittings f
on( jf.FITTING_NAME = f.FITTING_NAME)
group by jf.JOB_ID;
Output
What is the query to calculate total cost of a job_id with both wages and fitting cost? Can the sum from both queries be joined?
The best way is to break down the query into two simple queries and then join them together. This solution assumes that a job will always have someone working it but might not have any fitting costs (hence the left join from wages to fittings). Really this is a deficiency in the schema design as there should be a job table (maybe there is one that you haven't included in your example) which you would left join both wages and fittings to.
WITH job_wage_costs AS
(
SELECT job_id,
SUM(hours) * 30 AS wage_costs
FROM staff_on_job
GROUP BY job_id
),
job_fitting_costs AS (
SELECT job_id,
SUM(COST) AS fitting_costs
FROM job_fittings jf
JOIN fittings f ON (f.fitting_name = jf.fitting_name)
GROUP BY job_id
)
SELECT jw.job_id,
jw.wage_costs,
jf.fitting_costs
FROM job_wage_costs jw
LEFT OUTER JOIN job_fitting_costs jf ON (jf.job_id = jw.job_id);
JOB_ID WAGE_COSTS FITTING_COSTS
1 60 20
2 480 164.99
6 1200 199.99
12 1200 320.98
9 90
As an aside, the design of your fittings table could do with changing as it isn't a normalized design. By reproducing the fitting type in every row you make it very difficult to change the wording of those fitting types in the future as you'd need to change every row - they should be in a fitting_type table which can then be joined to fittings.
the easiest solution is to join your 2 query:
select A.job_id, A.wages,B.fittingcost, total = A.wages + B.fittingcost
from (
select job_id ,sum(hours*30) wages from staffs_on_job group by job_id
) A
join (
select jf.job_id ,sum(f.cost) fittingcost
from jobs_fittings jf left OUTER JOIN fittings f
on( jf.FITTING_NAME = f.FITTING_NAME)
group by jf.JOB_ID
) B on (A.job_id = B.job_id)
be aware that the above will not properly handle the case when one of the 2 tables does not contain the job_id you are looking for; if one of the tables does not contain that job_id then the result will be completely empty.
Related
I have a table which as huge records in table
My tables : employee and customer
Now the issue here is I have 2 billion records in employee table and 1 billion records in customer table
Employee columns
empid
empname
empage
empdcourse
Customer columns
custid
custdesc
custmessage
My query :
select emp_id from employee where empid not in ( select custid from customer);
Error : It throws me table space issue. Not allowed to increase table space
Is their any way I can tune my query or run in batch by batch so I get output
Any solution is much appreciated !!!
Need it on high priority
NOT EXISTS may be more efficient and less memory consuming in such case.
(The query suggests Customer and Employee share the same PK, does it mean you have an "super" table Person ?)
Try this:
with tmp as
(select /*+full(c)*/
custid
from customer c)
select /*+full(e)*/
e.emp_id
from employee e, tmp t
where e.empid = t.custid(+)
and t.custid is null;
The hint full will prevent the tablespace issue.
The OUTER JOIN is faster than the NOT IN.
You can improve it by adding the hint parallel, starting with a degree=2 or 4 like this:
with tmp as
(select /*+full(c) parallel(c,2)*/
custid
from customer c)
select /*+full(e) parallel(e,2)*/
e.emp_id
from employee e, tmp t
where e.empid = t.custid(+)
and t.custid is null;
You can add indexes for columns, for example, if they aren’t primary keys:
CREATE INDEX empid_index
ON employee(empid);
Also, you can update the query:
select e.empid from employee e where not exists (select 1 from customer c where c.custid = e.empid);
I am learning postgresql and Inner join I have following table.
Employee
Id Name DepartmentId
1 John S. 1
2 Smith P. 1
3 Anil K. 2
Department
Department
Id Name
1 HR
2 Admin
I want to query to return the Department Name and numbers of employee in each department.
SELECT Department.name , COUNT(Employee.id) FROM Department INNER JOIN Employee ON Department.Id = Employee.DepartmentId Group BY Employee.department_id;
I dont know what I did wrong as I am new to database Query.
When involving all rows or major parts of the "many" table, it's typically faster to aggregate first and join later. Certainly the case here, since we are after counts for "each department", and there is no WHERE clause at all.
SELECT d.name, COALESCE(e.ct, 0) AS nr_employees
FROM department d
LEFT JOIN (
SELECT department_id AS id, count(*) AS ct
FROM employee
GROUP BY department_id
) e USING (id);
Also made it a LEFT [OUTER] JOIN, to keep departments without any employees in the result. And COALESCE to report 0 employees instead of NULL in that case.
Related, with more explanation:
Query with LEFT JOIN not returning rows for count of 0
Your original query would work too, after fixing the GROUP BY clause:
SELECT department.name, COUNT(employee.id)
FROM department
INNER JOIN employee ON department.id = employee.department_id
Group BY department.id; --!
That's assuming department.id is the PRIMARY KEY of the table, in which case it covers all columns of that table, including department.name. And you may want LEFT JOIN like above.
Aside: Consider legal, lower-case names exclusively in Postgres. See:
Are PostgreSQL column names case-sensitive?
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 am trying to convert the following query:
select *
from employees
where emp_id not in (select distinct emp_id from managers);
into a form where I represent the subquery as a join. I tried doing:
select *
from employees a, (select distinct emp_id from managers) b
where a.emp_id!=b.emp_id;
I also tried:
select *
from employees a, (select distinct emp_id from managers) b
where a.emp_id not in b.emp_id;
But it does not give the same result. I have tried the 'INNER JOIN' syntax as well, but to no avail. I have become frustrated with this seemingly simple problem. Any help would be appreciated.
Assume employee Data set of
Emp_ID
1
2
3
4
5
6
7
Assume Manger data set of
Emp_ID
1
2
3
4
5
8
9
select *
from employees
where emp_id not in (select distinct emp_id from managers);
The above isn't joining tables so no Cartesian product is generated... you just have 7 records you're looking at...
The above would result in 6 and 7 Why? only 6 and 7 from Employee Data isn't in the managers table. 8,9 in managers is ignored as you're only returning data from employee.
select *
from employees a, (select distinct emp_id from managers) b
where a.emp_id!=b.emp_id;
The above didnt' work because a Cartesian product is generated... All of Employee to all of Manager (assuming 7 records in each table 7*7=49)
so instead of just evaluating the employee data like you were in the first query. Now you also evaluate all managers to all employees
so Select * results in
1,1
1,2
1,3
1,4
1,5
1,8
1,9
2,1
2,2...
Less the where clause matches...
so 7*7-7 or 42. and while this may be the answer to the life universe and everything in it, it's not what you wanted.
I also tried:
select *
from employees a, (select distinct emp_id from managers) b
where a.emp_id not in b.emp_id;
Again a Cartesian... All of Employee to ALL OF Managers
So this is why a left join works
SELECT e.*
FROM employees e
LEFT OUTER JOIN managers m
on e.emp_id = m.emp_id
WHERE m.emp_id is null
This says join on ID first... so don't generate a Cartesian but actually join on a value to limit the results. but since it's a LEFT join return EVERYTHING from the LEFT table (employee) and only those that match from manager.
so in our example would be returned as e.emp_Di = m.Emp_ID
1,1
2,2
3,3
4,4
5,5
6,NULL
7,NULL
now the where clause so
6,Null
7,NULL are retained...
older ansii SQL standards for left joins would have been *= in the where clause...
select *
from employees a, managers b
where a.emp_id *= b.emp_id --I never remember if the * is the LEFT so it may be =*
and b.emp_ID is null;
But I find this notation harder to read as the join can get mixed in with the other limiting criteria...
Try this:
select e.*
from employees e
left join managers m on e.emp_id = m.emp_id
where m.emp_id is null
This will join the two tables. Then we discard all rows where we found a matching manager and are left with employees who aren't managers.
Your best bet would probably be a left join:
select
e.*
from employees e
left join managers m on e.emp_id = m.emp_id
where
m.emp_id is null;
The idea here is you're saying that you want to select everything from employees, including anything that matches in the manager table based on emp_id and then filtering out the rows that actually have something in the manager table.
Use Left Outer Join instead
select e.*
from employees e
left outer join managers m
on e.emp_id = m.emp_id
where m.emp_id is null
left outer join will preserve the rows from m table even if they do not have a match i e table based on the emp_id field. The we filter on where m.emp_id is null - give me all the rows from e where there's no matching record in m table.
A bit more on the subject can be found here:
Visual representation of joins
from employees a, (select distinct emp_id from managers) b implies cross join - all posible combinations between tables (and you needed left outer join instead)
The MINUS keyword should do the trick:
SELECT e.* FROM employees e
MINUS
Select m.* FROM managers m
Hope that helps...
select *
from employees
where Not (emp_id in (select distinct emp_id from managers));