so I have 3 tables :
parkingZone -
ZID - zone id
Name - name of the zone
maxprice - max price of the parking zone
pricePerHour
carParking -
CID - the id of the car which parking
StartTime - start time of parking
EndTime - end time of parking
ParkingZoneID - zone ID (same as ZID in parkingzone)
Cost - how much the paking costed
Cars -
CID - same as CID in carParking
ID - ID of who owns the car
cellPhone - cellPhone of who ownsthe car
now I need to find the ID and CID of who has the max "cost" of the max "maxprice",
In other words, I need to find the ZID of the maximum "maxprice"
and then to find the ID and CID of the maximum "cost" related to "ZID"
so I managed to find all the CID that relates to the ZID:
select CarParking.CID, CarParking.Cost
from CarParking
inner join (select ParkingArea.AID
from ParkingArea
inner join(
select max(ParkingArea.maxpriceperday) maxpriceperday
from ParkingArea
)maxrow on maxrow.maxpriceperday = ParkingArea.maxpriceperday)maxCid on maxCid.AID= CarParking.ParkingAreaID
but how can I get the maximum cost, and then the CID AND ID from Cars table?
important note - there can be more then one max both in "maxpriceperday" and "Cost"
which means there could be more then one ZID with maxpriceperday(if they are equal)
and more then one maximum CID to each of those ZID (if the costs are equal).
so using "TOP" or "LIMIT" will not work.
for example:
how can I accomplish that?
thanks
This would be my approach:
First, select all ZID's with maxprice using a dense_rank. Next, use a second dense_rank to get all CID and with the highest cost from the selected ZID's. Finally, use the found CID's to get the Car-data.
That gives the CID's and ID's of all cars that have the highest (equal) cost in all lots with the highest maxprice.
If the dense_rank is new to you, you can read about it here
Gathered in one query:
SELECT CID
, ID
FROM Cars AS C
INNER JOIN (
SELECT CID
, Cost
, DENSE_RANK() over (ORDER BY Cost DESC) AS orderedCosts
FROM carParking AS CP
INNER JOIN (SELECT ZID
, DENSE_RANK() over (ORDER BY maxprice DESC) AS orderedMaxprice
FROM ParkingArea
) AS PA
ON PA.ZID= CP.ParkingAreaID
AND orderedMaxprice = 1
) as cars_most_costs
ON cars_most_costs.CID = C.CID
AND cars_most_costs.orderedCosts = 1
A dense_rank works like this:
ZID | maxprice| dense_rank
1 | 1000 | 1
3 | 1000 | 1
2 | 500 | 2
4 | 400 | 3
Using your paper example:
First step gets ZID 1 and 3, which both have the highest maxprice.
Next step gets CID 1010 and 1011, which are the cars with the higest cost on parkingzoneID's 1 and/or 3.
Final step returns CID/ID combo's 1010/2000 and 1011/2001.
The result you provided is actually wrong, because CID 1014 has a cost of 10 while the other two have 20.
If you meant max cost per parkingzoneID, then the question was not very clear, but you only have to change one line:
, DENSE_RANK() over (PARTITION BY ZID ORDER BY Cost DESC) AS orderedCosts
This will also return car 1014/2004
Related
I have this table. The table just a small example and has more obs.
id
CATEGORY
AMOUNT
1
TECH
120
1
FUN
220
2
OTHER
340
2
PARENTS
220
made by id category amount spent in each category.I want to select ID and Category in which the ID spents the most but in case if category is OTHER I want to get 2nd most spending category.
I have a constraint. I CANNOT use the the subquery and select with filter WHERE CATEGORY <> 'OTHER'. It just makes my machine to go out of the memory (For reasons Idk)
This is what I have tried.
I have tried to create a row_number () over (partition by id order by amount desc) rn.
and then
select id, category from table where row num = 1 group by 1,2
**buttt. I don't know how to say to query. If CATEGORY is OTHER then take row num=2 . **
id
CATEGORY
AMOUNT
ROW NUM
1
TECH
120
2
1
FUN
220
1
2
OTHER
340
1
2
PARENTS
220
2
Another thing I was thinking to do is to write qualify function
QUALIFY ROW_NUMBER() OVER (PARTITION BY ID ORDER BY AMOUNT DESC) <1.
Also here I am getting only 1st records in which there is also OTHER. If I could filter it out within QUALIFY and say if CATEGORY is 'OTHER' don't consider it.
I am using Databricks.
I need to write a query (Microsoft SQL Server) to delete duplicates in the table Vehicle that have Vehicle.CarId = Car.CarId and having the same concatenation (CarId, CounterLimit, Kilometers).
Table Car:
CarId
-----
11111
Table Vehicle:
VehicleId CarId CounterLimit Kilometers
-----------------------------------------------------
1 11111 250 120000
2 23456 300 150000
3 11111 250 120000 (record duplicated with 1, should be deleted)
Could you please help me?
Delete rows with lesser VehicleId
delete v
from Vehicle v
where exists (
select 1
from Vehicle v2
where v2.VehicleId > v.VehicleId
and v2.CarId = v.CarId and v2.CounterLimit = v.CounterLimit and v2.Kilometers = v.Kilometers)
To just query the table
select max(vehicleid) vehicleid, carid, CounterLimit, Kilometers
from Vehicle
group by carid, CounterLimit, Kilometers
Joining the table
creating the rank based on carid,counter limit, kilometer. If all three are same it is considered as duplicate. If you need to add more or less number of columns in this criteria you can adjust this part
next we take just one of the above row , meaning we eliminate the duplicates using rank_1 = 1
with rank as (
select
vehicle.vehicleid,
vehicle.carid,
vehicle.CounterLimit,
vehicle.Kilometers,
row_number() over(partition by vehicle.carid,vehicle.CounterLimit, vehicle.Kilometers order by vehicle.vehicleid) as rank_
from a vehicle
left join car
on Vehicle.CarId =car.carid
)
select * from rank where rank_ = 1
I am using PostgreSQL 9.3 version database.
I have a situation where I want to count the number of products sales and sum the amount of product and also want to show the cities in a column where the product have sale.
Example
Setup
create table products (
name varchar(20),
price integer,
city varchar(20)
);
insert into products values
('P1',1200,'London'),
('P1',100,'Melborun'),
('P1',1400,'Moscow'),
('P2',1560,'Munich'),
('P2',2300,'Shunghai'),
('P2',3000,'Dubai');
Crosstab query:
select * from crosstab (
'select name,count(*),sum(price),city,count(city)
from products
group by name,city
order by name,city
'
,
'select distinct city from products order by 1'
)
as tb (
name varchar(20),TotalSales bigint,TotalAmount bigint,London bigint,Melborun bigint,Moscow bigint,Munich bigint,Shunghai bigint,Dubai bigint
);
Output
name totalsales totalamount london melborun moscow munich shunghai dubai
---------------------------------------------------------------------------------------------------------
P1 1 1200 1 1 1
P2 1 3000 1 1 1
Expected Output:
name totalsales totalamount london melborun moscow munich shunghai dubai
---------------------------------------------------------------------------------------------------------
P1 3 2700 1 1 1
P2 3 6860 1 1 1
Your first mistake seems to be simple. According to the 2nd parameter of the crosstab() function, 'Dubai' must come as first city (sorted by city). Details:
PostgreSQL Crosstab Query
The unexpected values for totalsales and totalamount represent values from the first row for each name group. "Extra" columns are treated like that. Details:
Pivot on Multiple Columns using Tablefunc
To get sums per name, run window functions over your aggregate functions. Details:
Get the distinct sum of a joined table column
select * from crosstab (
'select name
,sum(count(*)) OVER (PARTITION BY name)
,sum(sum(price)) OVER (PARTITION BY name)
,city
,count(city)
from products
group by name,city
order by name,city
'
-- ,'select distinct city from products order by 1' -- replaced
,$$SELECT unnest('{Dubai,London,Melborun
,Moscow,Munich,Shunghai}'::varchar[])$$
) AS tb (
name varchar(20), TotalSales bigint, TotalAmount bigint
,Dubai bigint
,London bigint
,Melborun bigint
,Moscow bigint
,Munich bigint
,Shunghai bigint
);
Better yet, provide a static set as 2nd parameter. Output columns are hard coded, it may be unreliable to generate data columns dynamically. If you a another row with a new city, this would break.
This way you can also order your columns as you like. Just keep output columns and 2nd parameter in sync.
Honestly I think your database needs some drastic normalization and your results in several columns (one for each city name) is not something I would do myself.
Nevertheless if you want to stick to it you can do it this way.
For the first step you need get the correct amounts. This would do the trick quite fast:
select name, count(1) totalsales, sum(price) totalAmount
from products
group by name;
This will be your result:
NAME TOTALSALES TOTALAMOUNT
P2 3 6860
P1 3 2700
You would get the Products/City this way:
select name, city, count(1) totalCityName
from products
group by name, city
order by name, city;
This result:
NAME CITY TOTALCITYNAME
P1 London 1
P1 Melborun 1
P1 Moscow 1
P2 Dubai 1
P2 Munich 1
P2 Shunghai 1
If you really would like a column per city you could do something like:
select name,
count(1) totalsales,
sum(price) totalAmount,
(select count(1)
from Products a
where a.City = 'London' and a.name = p.name) London,
...
from products p
group by name;
But I would not recommend it!!!
This would be the result:
NAME TOTALSALES TOTALAMOUNT LONDON ...
P1 3 2700 1
P2 3 6860 0
Demonstration here.
I have a little problem.
My table is:
Bill Product ID Units Sold
----|-----------|------------
1 | 10 | 25
1 | 20 | 30
2 | 30 | 11
3 | 40 | 40
3 | 20 | 20
I want to SELECT the product which has sold the most units; in this sample case, it should be the product with ID 20, showing 50 units.
I have tried this:
SELECT
SUM(pv."Units sold")
FROM
"Products" pv
GROUP BY
pv.Product ID;
But this shows all the products, how can I select only the product with the most units sold?
Leaving aside for the moment the possibility of having multiple products with the same number of units sold, you can always sort your results by the sum, highest first, and take the first row:
SELECT pv."Product ID", SUM(pv."Units sold")
FROM "Products" pv
GROUP BY pv."Product ID"
ORDER BY SUM(pv."Units sold") DESC
LIMIT 1
I'm not quite sure whether the double-quote syntax for column and table names will work - exact syntax will depend on your specific RDBMS.
Now, if you do want to get multiple rows when more than one product has the same sum, then the SQL will become a bit more complicated:
SELECT pv.`Product ID`, SUM(pv.`Units sold`)
FROM `Products` pv
GROUP BY pv.`Product ID`
HAVING SUM(pv.`Units sold`) = (
select max(sums)
from (
SELECT SUM(pv2.`Units sold`) as "sums"
FROM `Products` pv2
GROUP BY pv2.`Product ID`
) as subq
)
Here's the sqlfiddle
SELECT SUM(pv."Units sold") as `sum`
FROM "Products" pv
group by pv.Product ID
ORDER BY sum DESC
LIMIT 1
limit 1 + order by
The Best and effective way to this is Max function
Here's The General Syntax of Max function
SELECT MAX(ID) AS id
FROM Products;
and in your Case
SELECT MAX(Units Sold) from products
Here is the Complete Reference to MIN and MAX functions in Query
Click Here
I have this table:
id | owner | asset | rate
-------------------------
1 | 1 | 3 | 1
2 | 1 | 4 | 2
3 | 2 | 3 | 3
4 | 2 | 5 | 4
And i'm using
SELECT asset, max(rate)
FROM test
WHERE owner IN (1, 2)
GROUP BY asset
HAVING count(asset) > 1
ORDER BY max(rate) DESC
to get intersection of assets for specified owners with best rate.
I also need id of row used for max(rate), but i can't find a way to include it to SELECT. Any ideas?
Edit:
I need
Find all assets that belongs to both owners (1 and 2)
From the same asset i need only one with the best rate (3)
I also need other columns (owner) that belongs to the specific asset with best rate
I expect the following output:
id | asset | rate
-------------------------
3 | 3 | 3
Oops, all 3s, but basically i need id of 3rd row to query the same table again, so resulting output (after second query) will be:
id | owner | asset | rate
-------------------------
3 | 2 | 3 | 3
Let's say it's Postgres, but i'd prefer reasonably cross-DBMS solution.
Edit 2:
Guys, i know how to do this with JOINs. Sorry for misleading question, but i need to know how to get extra from existing query. I already have needed assets and rates selected, i just need one extra field among with max(rate) and given conditions if it's possible.
Another solution that might or might not be faster than a self join (depending on the DBMS' optimizer)
SELECT id,
asset,
rate,
asset_count
FROM (
SELECT id,
asset,
rate,
rank() over (partition by asset order by rate desc) as rank_rate,
count(asset) over (partition by null) as asset_count
FROM test
WHERE owner IN (1, 2)
) t
WHERE rank_rate = 1
ORDER BY rate DESC
You are dealing with two questions and trying to solve them as if they are one. With a subquery, you can better refine by filtering the list in the proper order first (max(rate)), but as soon as you group, you lose this. As such, i would set up two queries (same procedure, if you are using procedures, but two queries) and ask the questions separately. Unless ... you need some of the information in a single grid when output.
I guess the better direction to head is to have you show how you want the output to look. Once you bake the input and the output, the middle of the oreo is easier to fill.
SELECT b.id, b.asset, b.rate
from
(
SELECT asset, max(rate) maxrate
FROM test
WHERE owner IN (1, 2)
GROUP BY asset
HAVING count(asset) > 1
) a, test b
WHERE a.asset = b.asset
AND a.maxrate = b.rate
ORDER BY b.rate DESC
You don't specify what type of database you're running on, but if you have analytical functions available you can do this:
select id, asset, max_rate
from (
select ID, asset, max(rate) over (partition by asset) max_rate,
row_number() over (partition by asset order by rate desc) row_num
from test
where owner in (1,2)
) q
where row_num = 1
I'm not sure how to add in the "having count(asset) > 1" in this way though.
This first searches for rows with the maximum rate per asset. Then it takes the highest id per asset, and selects that:
select *
from test
inner join
(
select max(id) as MaxIdWithMaxRate
from test
inner join
(
select asset
, max(rate) as MaxRate
from test
group by
asset
) filter
on filter.asset = test.asset
and filter.MaxRate = test.rate
group by
asset
) filter2
on filter.MaxIdWithMaxRate = test.id
If multiple assets share the maximum rate, this will display the one with the highest id.