I have the following SQL statement. It's throws the following error: "Only a single result allowed for a SELECT that is part of an expression". The goal of my sql statement is to get the name of the employee who made the 'cheapest' bribe.
The part between the brackets return the employee_id and the money it costs a day (of the relative cheapest bribe). These are two results while I only want the employee_id. So I just want to use the MIN part to get the right employee_id. How can I do this?
SELECT Voornaam, Achternaam
FROM Medewerker m JOIN
(
SELECT Medewerker_id
FROM Steekpenning
ORDER BY -1*Bedrag/(julianday(Begindatum) - julianday(Einddatum))
limit 1
) s
on m.Medewerker_id = s.Medewerker_id;
EDITED the answer. How can I expand this query to only show the bribes started this month? I think I need to use something like this? (julianday(Begindatum) - julianday('now')) > 31 but where?
Regards.
Cas
I think the following will work in SQLite:
select Firstname, Surname
from Employee e join
(select employee_id
from bribe
order by -1*Amount/(julianday(Startdate) - julianday(Enddate))
limit 1
) b
on e.employee_id = b.employee_id;
Related
Find Melbourne VIP level 4 customers’ first name, last name who have hired the vehicle model as “Ranger ” at least 2 times in database. You write three different queries: one is using operator EXISTS and the other one is using operator IN. The third query with the main filter criteria in FROM clause of the main query or filter criteria in the sub-query. Find one with the better performance.
I Have tried this query;
SELECT c_fname, c_fname FROM rental WHERE
EXISTS(SELECT c_id FROM customer WHERE c_city = 'Melbourne' AND customer.vip_level = '4')
AND EXISTS (SELECT vehicle_reg FROM vehicle WHERE v_model = 'Ranger')
HAVING COUNT(c_id)>=2 GROUP BY c_lname, c_fname;
I am getting error: SQL Error: ORA-00934: group function is not allowed here
00934. 00000 - "group function is not allowed here"
can anyone help me with this question. really struggled to get this done?
You are selecting from the wrong subject table as Rental does not have c_fname or c_lname columns.
You want to "Find Melbourne VIP level 4 customers’ first name, last name" which would be in the customer table:
SELECT c_fname,
c_lname
FROM customer
WHERE c_city = 'Melbourne'
AND vip_level = 4;
Then you want to add an additional filter "who have hired the vehicle model as “Ranger ” at least 2 times in database". That requires you to use EXISTS (for the answer for the first query) and you need to correlate between the outer-query and the sub-query; once you have done that then you do not need a GROUP BY clause and you are aggregating over the entire result set of the sub-query and can just use a HAVING clause.
SELECT c_fname,
c_lname
FROM customer c
WHERE c_city = 'Melbourne'
AND vip_level = 4
AND EXISTS(
SELECT 1
FROM rental r
INNER JOIN vehicle v
ON (r.vehicle_reg = v.vehicle_reg)
WHERE c.c_id = r.c_id
AND v.v_model = 'Ranger'
HAVING COUNT(*) >= 2
);
Then you need to write the same query using IN instead of EXISTS and the same query a third time using JOIN conditions instead of IN or EXISTS and, finally, you need to compare the performance of all three queries.
I have a table named Ticket Numbers, which (for this example) contain the columns:
Ticket_Number
Assigned_Group
Assigned_Group_Sequence_No
Reported_Date
Each ticket number could contain 4 rows, depending on how many times the ticket changed assigned groups. Some of these rows could contain an assigned group of "Desktop Support," but some may not. Here is an example:
Example of raw data
What I am trying to accomplish is to get the an output that contains any ticket numbers that contain 'Desktop Support', but also the assigned group of the max sequence number. Here is what I am trying to accomplish with SQL:
Queried Data
I'm trying to use SQL with the following query but have no clue what I'm doing wrong:
select ih.incident_number,ih.assigned_group, incident_history2.maxseq, incident_history2.assigned_group
from incident_history_public as ih
left join
(
select max(assigned_group_seq_no) maxseq, incident_number, assigned_group
from incident_history_public
group by incident_number, assigned_group
) incident_history2
on ih.incident_number = incident_history2.incident_number
and ih.assigned_group_seq_no = incident_history2.maxseq
where ih.ASSIGNED_GROUP LIKE '%DS%'
Does anyone know what I am doing wrong?
You might want to create a proper alias for incident_history. e.g.
from incident_history as incident_history1
and
on incident_history1.ticket_number = incident_history2.ticket_number
and incident_history1.assigned_group_seq_no = incident_history2.maxseq
In my humble opinion a first error could be that I don't see any column named "incident_history2.assigned_group".
I would try to use common table expression, to get only ticket number that contains "Desktop_support":
WITH desktop as (
SELECT distinct Ticket_Number
FROM incident_history
WHERE Assigned_Group = "Desktop Support"
),
Than an Inner Join of the result with your inner table to get ticket number and maxSeq, so in a second moment you can get also the "MAXGroup":
WITH tmp AS (
SELECT i2.Ticket_Number, i2.maxseq
FROM desktop D inner join
(SELECT Ticket_number, max(assigned_group_seq_no) as maxseq
FROM incident_history
GROUP BY ticket_number) as i2
ON D.Ticket_Number = i2.Ticket_Number
)
SELECT i.Ticket_Number, i.Assigned_Group as MAX_Group, T.maxseq, i.Reported_Date
FROM tmp T inner join incident_history i
ON T.Ticket_Number = i.Ticket_Number and i.assigned_group_seq_no = T.maxseq
I think there are several different method to resolve this question, but I really hope it's helpful for you!
For more information about Common Table Expression: https://www.essentialsql.com/introduction-common-table-expressions-ctes/
I have an SQL sentence :
SELECT application.id,title,url,company.name AS company_name,package_name,ranking,date,platform,country.name AS country_name,collection.name AS collection_name,category.name AS category_name FROM application
JOIN application_history ON application_history.application_id = application.id
JOIN company ON application.company_id = company.id
JOIN country ON application_history.country_id = country.id
JOIN collection ON application_history.collection_id = collection.id
JOIN category ON application_history.category_id = category.id
WHERE application.platform=0
AND country.name ='CZ'
AND collection.name='topfreeapplications'
AND category.name='UTILITIES'
AND application_history.ranking <= 10
AND date::date BETWEEN date (CURRENT_DATE - INTERVAL '1 month') AND CURRENT_DATE
ORDER BY application_history.ranking ASC
It produces this result :
I'd like to add both a column average ranking for a given package, and a column number of appearances, which would count the number a package appears in the list. I'd also like to Group results by package_name, so that I don't have redundancies.
So far, I've tried to add a GROUP BY By clause before the ORDER BY :
GROUP BY package_name
But it returns me an error :
column "application.id" must appear in the GROUP BY clause or be used in an aggregate function
If I add each and every column it asks me for, it doesn't work.
I have also tried to count the number of package names, by adding after the SELECT :
COUNT(package_name) AS count
It produces a similar error.
How could I get the result I'm looking for ? Should I make two queries instead, or is it possible to get everything at once ?
I precise I have looked at other answers on S.O, but none of them tries to make the COUNT on a "produced" column.
Thank you for your help.
Edit :
Here is the result I expected at first :
Although Gordon's advice didn't give me the proper result it put me on the good track, when I read this :
From the docs : "Unlike regular aggregate functions, use of a window function does not cause rows to become grouped into a single output row."
So I came back to using COUNT and AVG alone. My problem was that I wanted to display the ranking column and date to check whether things were right. But putting these column into the Select prevented the GROUP BY to work as expected, as mentioned by Jarlh in the comments.
The working query :
SELECT application.id,title,url,company.name AS company_name,package_name,platform,country.name AS country_name,collection.name AS collection_name,category.name AS category_name,
COUNT(package_name) AS count, AVG(application_history.ranking) AS avg
FROM application
JOIN application_history ON application_history.application_id = application.id
JOIN company ON application.company_id = company.id
JOIN country ON application_history.country_id = country.id
JOIN collection ON application_history.collection_id = collection.id
JOIN category ON application_history.category_id = category.id
WHERE application.platform=0
AND country.name ='CZ'
AND collection.name='topfreeapplications'
AND category.name='UTILITIES'
AND application_history.ranking <= 10
AND date::date BETWEEN date (CURRENT_DATE - INTERVAL '1 month') AND CURRENT_DATE
GROUP BY package_name,application.id,company.name,country.name,collection.name,category.name
ORDER BY count DESC
I think you want window/analytic functions. The following adds two columns, one for the count of rows for each package and the other an average ranking for them:
SELECT application.id, title, url, company.name AS company_name, package_name,
ranking, date, platform, country.name AS country_name,
collection.name AS collection_name, category.name AS category_name,
count(*) over (partition by package_name) as count,
avg(ranking) over (partition by package_name) as avg_package_ranking
FROM application . . .
I have a problem that I hope you can help me.
I have the next query on Access SQL.
SELECT
ID_PLAN_ACCION, ID_SEGUIMIENTO,
Max(FECHA_SEGUIMIENTO) AS MAX_FECHA
FROM
SEGUIMIENTOS
WHERE
(((ID_PLAN_ACCION) = [CODPA]))
GROUP BY
ID_PLAN_ACCION, ID_SEGUIMIENTO;
And it returns this information:
ID_PLAN_ACCION ID_SEGUIMIENTO MAX_FECHA
-----------------------------------------------
A1-01 1 16/01/2014
A1-01 2 30/01/2014
But I really need that it throws off this:
ID_PLAN_ACCION ID_SEGUIMIENTO MAX_FECHA
----------------------------------------------
A1-01 2 30/01/2014
As you can see I only need the record that has the most recently date, not all the records
The GROUP BY doesn't work.
Please can you tell me what can I do? I am new on all this.
Thank you so much!!
PD: Sorry for my english, I'm learning
This will produce the results you want:
SELECT ID_PLAN_ACCION, max(ID_SEGUIMIENTO) as ID_SEGUIMIENTO, Max(FECHA_SEGUIMIENTO) AS MAX_FECHA
FROM SEGUIMIENTOS
WHERE ID_PLAN_ACCION = [CODPA]
GROUP BY ID_PLAN_ACCION;
I removed id_sequiimiento from the group by and added an aggregation function to get the max value. If the ids increase along with the date, this will work.
Another way to approach this query, though, is to use top and order by:
SELECT top 1 ID_PLAN_ACCION, ID_SEGUIMIENTO, FECHA_SEGUIMIENTO
FROM SEGUIMIENTOS
WHERE ID_PLAN_ACCION = [CODPA]
ORDER BY FECHA_SEGUIMIENTO desc;
This works because you are only returning one row.
EDIT:
If you have more codes, that you are looking at, you need a more complicated query. Here is an approach using where/not exists:
SELECT ID_PLAN_ACCION, ID_SEGUIMIENTO, FECHA_SEGUIMIENTO
FROM SEGUIMIENTOS s
WHERE not exists (select 1
from SEGUIMIENTOS s2
where s.ID_PLAN_ACCION = s2.ID_PLAN_ACCION and
s2.FECHA_SEGUIMIENTO > s.FECHA_SEGUIMIENTO
)
ORDER BY FECHA_SEGUIMIENTO desc;
You can read this as: "Get me all rows from SEGUIMIENTOS where there is no other row with the same ID_PLAN_ACCION that has a larger date". Is is another way of saying that the original row has the maximum date.
I have two tables. First is a table Employees the second is TimeCard. I am trying to determine when employees are not here. Sample Tables:
So an employee name is returned if it meets the following criteria: Status = 1 and Date != '8/27/13'. However I only want an Employee returned once even if they have multiple entires in the TimeCard table as long as they are not on a specified date.
Try the following:
SELECT e.employee FROM employees e
WHERE status=1
AND NOT EXISTS ( SELECT 1 FROM timecard t
WHERE t.employee=e.employee
AND t.Date = '8/27/13')
where '8/27/13' will work only, if date is a varchar column. Otherwise you should use a more standard date format like '2013-8-27'.
Edit:
In MSSQL '8/27/13' will actually work, but it is still not a good idea to use this notation as it is not unambiguous when smaller numbers are used, like '5/6/7'. Depending on who entered it (and from which country they come), this could mean either May 6 2007, or 2005 May the 7th or 5 June 2007 ...
2. Edit:
Evidently not a good idea to prepare supper while you are putting together a SQLfiddle! The whole thing was buggy. I just fixed it and, of course corrected the typo with t.Date != '8/27/13' sorry for the confusion! See the corrected fiddle here: http://sqlfiddle.com/#!3/26454/1
Try this:
SELECT DISTINCT e.employee
FROM employees e
LEFT JOIN timecard t ON t.employee = e.employee
WHERE e.status = 1 AND (t.date != '8/27/13' OR t.date IS NULL)