I'm having an absolute brain fade
SELECT p.ProductCategory, f.ProductSubCategory, COUNT(*) AS Cnt
FROM Sales f
JOIN Products p ON f.ProductSubCategory = p.ProductSubCategory
GROUP BY p.ProductCategory, f.ProductSubCategory
ORDER BY 1,3 DESC
This shows me the count for each ProductSubCategory, I would like to see only the highest ProductSubCategory per ProductCategory.
I wish to see (I don't care about the Count value)
There are a couple of different ways to do this. One involves joining the results back to themselves and using the max aggregate. But since you are using SQL Server, you can use ROW_NUMBER to achieve the same result:
with cte as (
select p.productcategory, p.ProductSubCategory, COUNT(*) cnt,
ROW_NUMBER() over (partition by p.productcategory order by count(*) desc) rn
from products p
join sales s on p.ProductSubCategory = s.ProductSubCategory
group by p.productcategory, p.ProductSubCategory
)
select *
from cte
where rn = 1
You already got the answer, Please see the following code to. It may help you.
SELECT p.ProductCategory,
f.ProductSubCategory,
COUNT(*) AS Cnt
FROM Sales f
JOIN Products p ON f.ProductSubCategory = p.ProductSubCategory
JOIN (
SELECT p.ProductCategory,
f.ProductSubCategory,
ROW_NUMBER() OVER ( PARTITION BY p.ProductCategory,
f.ProductSubCategory
ORDER BY COUNT(*) DESC) [Row]
FROM Sales f
JOIN Products p ON f.ProductSubCategory = p.ProductSubCategory) Lu
ON P.ProductCategory = Lu.ProductCategory
AND f.ProductSubCategory = Lu.ProductSubCategory
WHERE Lu.Row = 1
GROUP By p.ProductCategory,
f.ProductSubCategory
Related
We have many old selects like this:
SELECT
tm."ID",tm."R_PERSONES",tm."R_DATASOURCE", ,tm."MATCHCODE",
d.NAME AS DATASOURCE,
p.PDID
FROM TABLE_MAPPINGS tm,
PERSONES p,
DATASOURCES d,
(select ID
from TABLE_MAPPINGS
where (R_PERSONES, MATCHCODE)
in (select
R_PERSONES, MATCHCODE
from TABLE_MAPPINGS
where
id in (select max(id)
from TABLE_MAPPINGS
group by MATCHCODE)
)
) tm2
WHERE tm.R_PERSONES = p.ID
AND tm.R_DATASOURCE=d.ID
and tm2.id = tm.id;
These are large tables, and queries take a long time.
How to rebuild them?
Thank you
You can query the table only once using something like (untested as you have not provided a minimal example of your create table statements or sample data):
SELECT *
FROM (
SELECT m.*,
COUNT(CASE WHEN rnk = 1 THEN 1 END)
OVER (PARTITION BY r_persones, matchcode) AS has_max_id
FROM (
SELECT tm.ID,
tm.R_PERSONES,
tm.R_DATASOURCE,
tm.MATCHCODE,
d.NAME AS DATASOURCE,
p.PDID,
RANK() OVER (PARTITION BY tm.matchcode ORDER BY tm.id DESC) As rnk
FROM TABLE_MAPPINGS tm
INNER JOIN PERSONES p ON tm.R_PERSONES = p.ID
INNER JOIN DATASOURCES d ON tm.R_DATASOURCE = d.ID
) m
)
WHERE has_max_id > 0;
First finding the maximum ID using the RANK analytic function and then finding all the relevant r_persones, matchcode pairs using conditional aggregation in a COUNT analytic function.
Note: you want to use the RANK or DENSE_RANK analytic functions to match the maximums as it can match multiple rows per partition; whereas ROW_NUMBER will only ever put a single row per partition first.
You're querying table_mappings 3 times; how about doing it only once?
WITH
tab_map
AS
(SELECT a.id,
a.r_persones,
a.matchcode,
a.datasource,
ROW_NUMBER ()
OVER (PARTITION BY a.matchcode ORDER BY a.id DESC) rn
FROM table_mappings a)
SELECT tm.id,
tm.r_persones,
tm.matchcode,
d.name AS datasource,
p.pdid
FROM tab_map tm
JOIN persones p ON p.id = tm.r_persones
JOIN datasources d ON d.id = tm.r_datasource
WHERE tm.rn = 1
I would like to get the average of the top2 limit1 per policyid. I need my resulting table to also have objectid.
Limit1 and objectid come from the table p_coverage.
Policyid comes from the table p_risk.
The table p_item is a linking table between p_risk and p_coverage.
The way I thought I should build my query is: create a ranking of limit1 within each policyid. Then take the avg top2.
However the ranking doesn't work and give wrong result. My query works if I take columns from ONE table, but as soon as I add joins between them it gives false ranking.
SELECT policyid, limit1, /*pcob,*/ RANK() OVER(PARTITION BY policyid ORDER BY limit1 DESC) AS rn
FROM (SELECT policyid, limit1/*, pc.objectid ASpcob*/
FROM p_risk pr
LEFT JOIN p_item
ON pr.objectid=p_item.riskobjectid
LEFT JOIN p_coverage pc
ON p_item.objectid=pc.insuranceitemid) AS s
) AS SubQueryAlias
GROUP BY
policyid, limit1/*, pcob*/, rn
ORDER BY rn,policyid,limit1 DESC
The table at the end of the picture is what I'd like to have. The first table is the result of the query of Golden Linoff
If I understand correctly, you want the ROW_NUMBER() in the subquery and then to aggregate and filter in the outer query:
SELECT policyid, AVG(limit1) as avg_top2_limit1
FROM (SELECT policyid, limit1,
DENSE_RANK() OVER (PARTITION BY policyid ORDER BY limit1 DESC) as seqnum
FROM p_risk pr LEFT JOIN
p_item i
ON pr.objectid = i.riskobjectid LEFT JOIN
p_coverage pc
ON i.objectid = pc.insuranceitemid) AS s
) p
WHERE seqnum <= 2
GROUP BY policyid
thanks to previous comment! I succeed to do what I wanted. There is the query
select b.policyid, avg(b.limit1) as avg_top2_limit1 from(
SELECT distinct(policyid) policyid, limit1
FROM (SELECT policyid, limit1,
Dense_rank() OVER (PARTITION BY policyid ORDER BY limit1 DESC) as
seqnum
FROM p_risk pr LEFT JOIN
p_item i
ON pr.objectid = i.riskobjectid LEFT JOIN
p_coverage pc
ON i.objectid = pc.insuranceitemid) AS s
WHERE seqnum <= 2 ) as b
GROUP BY policyid`
I have a query where I am trying to get results from a table:
SELECT P.P_CODE, P.P_JEWELRYTYPE,P.p_catalog, P_AVAILABLE, P_RESERVED , p.p_catalog
FROM products P
WHERE
P.p_catalog IN (8796093383256,8796093252184,8796093317720,8796093121112,8796093186648);
I want a query where I can limit the number of results to 500 of each catalog type. How should I modify my query to achieve this?
Analytical function row_number() will work which will assign row numbers to each p_catalog so that you could filter on that condition in WHERE clause in an outer query:
SELECT *
FROM (
SELECT
p.P_CODE, p.P_JEWELRYTYPE, p.p_catalog, p.P_AVAILABLE, p.P_RESERVED, p.p_catalog,
row_number() over (partition by p.p_catalog) as rn
FROM products p
WHERE p.p_catalog IN (8796093383256,8796093252184,8796093317720,8796093121112,8796093186648)
) p
WHERE rn <= 500;
Use row_number():
select p.*
from (select p.*, row_number() over (partition by catalog order by null) as seqnum
from products p
) p
where p.seqnum <= 500;
You can put the where filtering in either the inner or outer query.
I'm struggling to right a SQL command to get the top 10 names from the following (using standard SQL, cant use TOP) for the following 2 relations:
Orders (customer_email, item_id, date)
Items(id, name, store, price)
Any advice on how to do this? I think I would need to group them, but then what do I do to get the top 10 groupings based on count?
select *
from (select x.*, row_number() over(order by num_orders desc) as rn
from (select i.name, count(*) as num_orders
from orders o
join items i
on o.item_id = i.id
group by i.name) x) x
where rn <= 10
SELECT
COUNT(*) count_per_item
, i.id
, i.name
FROM
Orders o
JOIN
Items i
ON (o.item_id = i.id)
GROUP BY
i.id
, i.name
ORDER BY
count_per_item DESC
LIMIT 10;
University Table - UniversityName, UniversityId
Lease Table - LeaseId, BookId, UniversityId, LeaseDate
Book Table - BookId, UniversityId, Category, PageCount.
For each university, I have to find category that had the most number of books leased.
So, something like
UniversityName Category #OfTimesLeased
I have been playing around with it with some success using Dense_Rank etc - but if there is a tie, only one of them shows up, while I want both of them to show up.
Current Query:
select b.UniversityId, MAX(tempTable.type) KEEP (DENSE_RANK FIRST ORDER BY tempTable.counter DESC)
from book b
join
(select count(l.leaseid) AS counter, b.category, b.universityid
from lease l
join book b
on b.bookid =l.bookid AND b.universityid=r.universityid
group by b.category, b.universityid) tempTable
on counterTable.universityid= b.universityid
group by b.universityid
^Unable to solve the tie issue and get the number of leases for the most leased book type.
Try this
WITH CTE AS
(
SELECT UniversityName, Category, Count(*) NumOfTimesLeased
FROM University u
INNER JOIN Book b on u.UniversityId = b.UniversityId
INNER JOIN Lease l on b.bookid = l.bookid and b.UniversityId = l.UniversityId
GROUP BY UniversityName, Category
),
CTE2 AS (
SELECT UniversityName, Category, NumOfTimesLeased,
RANK() OVER (PARTITION BY UniversityName
ORDER BY NumOfTimesLeased DESC) Rnk
FROM CTE)
SELECT * FROM CTE2 WHERE Rnk = 1
You are on the right track with the analytic functions:
select Univerity, Category, NumLeased
from (select t.*,
row_number() over (partition by university order by Numleased desc) as seqnum
from (select l.university, b.category, count(*) as NumLeased
from lease l join
book b
on l.bookid = b.bookid
group by l.university, b.category
) t
) t
where seqnum = 1
I use the row_number() because you only want the one top value. Rank and dense_rank are more useful when you are looking for values other than "1".
If you want the top values to show up when there is a tie, then use dense_rank instead of row_number. The values will be on different rows.