I'm sorry for my strange title, but I don't know what exactly I'm looking for. The task is quite simple. I have the table of competitions. Another table groups. In every group there are several contestants. In the last table are stored the results of contestants. The task is to get the first three of the contestants of every group.
So I have to loop through the groups, get the first three contestants (according to achieved points) of every group and append them into some variable.
Here is the pseudocode:
CREATE OR REPLACE PROCEDURE get_first_three_of_all(contestants OUT SOME_TYPE) AS
CURSOR groups SELECT...
BEGIN
FOR group IN groups LOOP
APPEND(contestants, get_first_three_of_one_group(group.id))
END LOOP;
END;
I have no idea, how to solve this task. I even don't know what should I look for. Would you be so kind and help me, please? Thanks.
Edited: simplified structure of my tables:
Competition: competition_id
Contestant: contestant_id
GroupContestant: contestant_group_id, competition_d, group_number, contestant_id
Result: contestant_group_id, juror, points
Select to get data of one group (group number YYY) is here:
SELECT * FROM (
SELECT res.contestant_group_id, SUM(res.points) AS points
FROM Result res
WHERE res.couple_group_id IN (SELECT couple_group_id
FROM GroupContestant
WHERE competition_id = XXX
AND group_number = YYY)
GROUP BY res.contestant_group_id
ORDER BY points DESC
)
WHERE ROWNUM <= 3;
Analytic functions to the rescue. To select top 3 results for each group, each competition:
SELECT * FROM (
SELECT grp.competition_id, grp.group_number, res.contestant_group_id, res.points,
row_number() over (partition by grp.competition_id, grp.group_number
order by res.points desc) rn
FROM (SELECT contestant_group_id, SUM(points) AS points
FROM Result
GROUP BY contestant_group_id) res
JOIN GroupContestant grp ON (grp.contestant_group_id = res.contestant_group_id)
)
WHERE rn <= 3;
Pay attention to how you resolve ties (consider using rank or dense_rank instead of row_number).
You can use RANK() analytic function to achieve the goal:
select *
from (select group_num,
points,
rank() over(partition by group_num order by points desc) rank
from results
inner join group_contestant
using (contestant_group_id))
where rank <= 3
order by group_num, points desc;
Here is SQLFiddle to play with.
Related
I have two tables on Oracle database, one is named departments_table and the other is locations_table. The departments.table has dep_id, dep_name, location_id, staff_id, employer_id. The locations table consists of location_id, city_id, streetname_id and postcode_id. How do I calculate the number of departments that each location has?
This is the code below is what I have tried to replicate but have been unsuccessful. The error message below that is what shows once the code has submitted.
SELECT dep_name, location_id,
COUNT(*)
FROM departments_table
WHERE location_id => 1
GROUP BY dep_name;
The results of this is an error, " not a single group function "
If you want to count how many departments are in each location, then you must group by location, not by department name, right? Let's start with that.
Then, you don't need ANYTHING about the individual departments in the output of the query, do you? You just need the location id and the count of departments.
select location_id, count(*) as cnt
from departments_table
group by location_id
;
This does most of the work. You may want to add the location name (city, address, etc.), which is/are stored elsewhere - in the locations_table. So you will need a join. And there may be locations in that table that are not, in fact, the location of any department (their id doesn't appear in the departments_table at all). If so, you would need an OUTER join. Also for those departments you probably want to show a count of 0 (rather than null) - you can "fix" that with the nvl() function. So you will end up with something like
select l.*, nvl(g.cnt, 0) as department_count
from locations_table l
left outer join
( select location_id, count(*) as cnt
from departments_table
group by location_id
) g
on l.location_id = g.location_id
;
SELECT l.location_id, l.city, COUNT(d.DEPARTMENT_ID)
FROM OEHR_LOCATIONS l, OEHR_DEPARTMENTS d WHERE l.location_id = d.location_id
GROUP BY l.location_id, l.city ORDER BY l.city;
This method works. I created aliases and made minor changes. OEHR stands for the table names so ignore that.
Hello I'am very new to writing SQL and I am trying to find the appropriate way to use TOP in Oracle SQl 9:
My example:
select * from example e, test t
where e.id = t.id
and country = 'USA'
order by state ASC;
What I am trying to do is take the bottom 20 % of my query but I know you cannot use TOP. After researching I still have not found an applicable answer. I know you have to first order them but am unsure of how to then take the bottom 20%(which would be TOP since the order is ASC)
In general (like if you want the top or bottom 17.2% of the rows) you can use row_number() and count() (analytic functions) to get the result.
20% is easier - you are looking for the top (or bottom) quintile. For this, you can use the ntile() function, like so:
select [column_names]
from (
select e.*, t.*, ntile(5) over (order by state) as nt
from ..... etc
)
where nt = 1;
The subquery is your query. The column_names in the outer query are whatever you actually need; you could also use select * but that will show the ntile too (which will be 1 in all rows).
If sorting something in ASCending order gives us the top set then surely sorting in DESCending order can give us the bottom set.
This solution uses the function NTILE() to divide the records into five buckets. The first bucket is the set we want (because sorted in descending order). Sorting in ascending order and taking the fifth quintile would have the same outcome.
select * from (
select e.*
, t.*
, ntile(5) over (order by state desc) nt
from example e, test t
where e.id = t.id
and country = 'USA'
)
where nt = 1
order by state desc
/
You don't say what your sort criteria are, so I've guessed.
CURSOR BULKUPDATE IS
SELECT SUM(B.ACCOUNT_BALANCE) AS ACCOUNT_BALANCE,C.CIF AS CIF_ID FROM _ACCOUNTS_STAGING2 B JOIN _RELATION_STAGING2 C
ON B.ACCOUNT_IDENTIFICATION_NUMBER = C.ACCOUNT_IDENTIFICATION_NUMBER AND B.SOURCEID=C.SOURCEID JOIN _CUSTOMER_STAGING2 A ON A.CIF=C.CIF AND A.SOURCEID=C.SOURCEID WHERE C.ROLE_ON_ACCOUNT IN
(Select Rollonaccount From _Roleaccount_Master Where Aggregatebalance='Y')
And upper(B.Scheme_Type) In (Select Scheme_Type From _Schema_Type_Master Where
Depository_Account = 'Y') Group By C.Cif;
Rec_Bulkupdate Bulkupdate%Rowtype;
I am using this query to sum account balances based on different cif and source. The question is I want to calculate four different types of sum on the basis of _Schema_Type_Master. For example I want to check now current_account='Y' instead of Depository_Account='Y'
_ACCOUNTS_STAGING2 B JOIN _RELATION_STAGING2 C
ON B.ACCOUNT_IDENTIFICATION_NUMBER = C.ACCOUNT_IDENTIFICATION_NUMBER AND B.SOURCEID=C.SOURCEID JOIN _CUSTOMER_STAGING2 A ON A.CIF=C.CIF AND A.SOURCEID=C.SOURCEID WHERE C.ROLE_ON_ACCOUNT IN
(Select Rollonaccount From _Roleaccount_Master Where Aggregatebalance='Y')
And upper(B.Scheme_Type) In (Select Scheme_Type From _Schema_Type_Master Where
current_account='Y') Group By C.Cif;
Rec_Bulkupdate Bulkupdate%Rowtype;
Is there any way or do I need to write four different cursors for that??
You can remove dipository_account='Y' and current_account='Y' and use case in select as -
SELECT SUM(CASE WHEN Depository_Account = 'Y' THEN B.ACCOUNT_BALANCE ELSE 0 END) AS DIPOSITORY_ACCOUNT_BALANCE,
SUM(CASE WHEN current_account = 'Y' THEN B.ACCOUNT_BALANCE ELSE 0 END) AS CURRENT_ACCOUNT_BALANCE
and then rest of your code. You will get two different columns for sum of Depository account and Current account.
And if filter for dipository_account='Y' and current_account='Y' is required, then use them in where condition with or operator :
AND (dipository_account='Y' or current_account='Y')
I know the "how to limit" or "how to get 1st row" has been posted many times but I can't find a solution to my specific issue.
I have a inventory balance table that contains bin # with quantities
I want on my row the bin # that contains the highest quantity
The real queries are much bigger and complex than this but this example shows the issue I am facing
I first I did
select itemnumber,
(select binnumber from inventory_balance where current_balance = (select max(current_balance) from inventory_balance where inventory_balance.itemnumber = item_table.itemnumber)) as binnumber
from item_table;
This will work when there is only one "bin" with the highest quantity.
If there are 2 bins for the same item with a quantity of 10 (which is the highest quantity), the sub query will return 2 rows, triggering a oracle error
Then I tried this :
select
itemnumber,
(select binnumber from (select binnumber from inventory_balance where current_balance = (select max(current_balance) from inventory_balance where inventory_balance.itemnumber = item_table.itemnumber)) where rownum =1) as binnumber
from item_table;
Now this will not work because it seems that the references to item_table.itemnumber is invalid when inside the from (...). I get "invalid column name" error when trying to do so.
I can't use ROW_NUMBER() because the "OLAP Window functions" do not seem to be activated on the database.
Something like this:
SELECT t.itemnumber,
MIN( b.binnumber ) KEEP ( DENSE_RANK LAST ORDER BY b.current_balance ASC ) AS binnumber
FROM item_table t
LEFT OUTER JOIN inventory_balance b
ON ( t.itemnumber = b.itemnumber )
GROUP BY t.itemnumber;
Looking at the explain plan then this will only scan inventory_balance once whereas doing nested selects to get the MAX balance and then filter an outer query based on that requires two scans of inventory_balance.
Although all the required output for you minimal working example seems to be contained in the inventory_balance table so you can do (if you are not interested in the itemnumbers where there are no entries in the inventory_balance table):
SELECT itemnumber,
MIN( binnumber ) KEEP ( DENSE_RANK LAST ORDER BY current_balance ASC ) AS binnumber
FROM inventory_balance
GROUP BY itemnumber;
If you want the highest binnumber (instead of the lowest) then you can just change it to:
MAX( binnumber ) KEEP ...
chaps and chapettes
Just a quick question. I need to return only one row from a stored proc., but no matter where I place the WHERE clause, I get errors. Can somebody take a look at the (cut-down due to sheer length) code and let me know where it should go, please?
SELECT **values**
INTO **variables**
FROM **table**
_WHERE ROWNUM = 1_
INNER JOIN **other table**
ON **join target**
ORDER BY **sort criteria**;
_WHERE ROWNUM = 1_
Thanks
I believe this is the way to structure rownum queries
SELECT * FROM
INTO **Variables * *
( SELECT * FROM X
WHERE Y
ORDER BY Z
)
WHERE ROWNUM = 1;
You were almost correct. You put the WHERE clause after the JOINs, but before the ORDER BY.
SELECT **values**
INTO **variables**
FROM **table**
INNER JOIN **other table**
ON **join target**
_WHERE ROWNUM = 1_
ORDER BY **sort criteria**;
However, this won't do what you might think - the ORDER BY is evaluated AFTER the where clause; which means this will just pick the first record it finds (that satisfies the join criteria), and will then sort that row (which obviously is a no-op).
The other answers (e.g. IvoTops') give ideas of how to get the first record according to the sort criteria.
SELECT **values**
INTO **variables**
FROM
( SELECT **values**
, ROW_MUMBER() OVER (ORDER BY **sort criteria**) AS rn
FROM **table**
INNER JOIN **other table**
ON **join target**
) tmp
WHERE rn = 1 ;
Check also this blog post: Oracle: ROW_NUMBER() vs ROWNUM
little bit late, but I got a similar problem and I solved it like this:
SELECT **values**
INTO **variables**
FROM **table**
WHERE **condition**
ORDER BY **sort criteria**
FETCH FIRST 1 ROW ONLY;
Regards