I want to write a SQL query to generate ranks of groups and subgroups based on third column (Price in this case). While i know we can use dense_rank() to generate ranks based on one column. I have no idea how to generate the two columns of ranks as shown below in a single query.
Both the rankings are based on price. So J3 comes first because J3 sum(price) is 1600. J1 comes second because J1 sum(price) is 1500 and so on.
Any inputs are appreciated.
I have provided the sample input and output. The name of the input table is "RENTAL"
First roll up jet_type prices to the jet_type level, then create a ranking of all jet_types ordered by rolled up price, and finally use your window function in the outer query partitioned by jet_price and ordered by highest rolled up price to create rank_service_wthin_jet:
select a.jet_type, b.rownum rank_jet, a.service_type, a.price,
row_number() over(partition by a.jet_type order by a.price desc) rank_service_wthin_jet
from yourtable a join (
select jet_type, row_number() over(order by price desc) rownum from (
select jet_type, sum(price) price from yourtable
group by jet_type)a)b on a.jet_type=b.jet_type
You can generate two columns as:
select t.*,
dense_rank() over (order by jet_type) as rank_jet,
row_number() over (partition by jet_type order by price desc) as rank_service_within_jet
. . .
This does not exactly return what is in your table. But the results are quite similar and -- even more important -- make sense.
Related
In SQL Server, I am attempting to pull the second latest NOTE_ENTRY_DT_TIME (items highlighted in screenshot). With the query written below it still pulls the latest date (I believe it's because of the grouping but the grouping is required to join later). What is the best method to achieve this?
SELECT
hop.ACCOUNT_ID,
MAX(hop.NOTE_ENTRY_DT_TIME) AS latest_noteid
FROM
NOTES hop
WHERE
hop.GEN_YN IS NULL
AND hop.NOTE_ENTRY_DT_TIME < (SELECT MAX(hope.NOTE_ENTRY_DT_TIME)
FROM NOTES hope
WHERE hop.GEN_YN IS NULL)
GROUP BY
hop.ACCOUNT_ID
Data sample in the table:
One of the "easier" ways to get the Nth row in a group is to use a CTE and ROW_NUMBER:
WITH CTE AS(
SELECT Account_ID,
Note_Entry_Dt_Time,
ROW_NUMBER() OVER (PARTITION BY AccountID ORDER BY Note_Entry_Dt_Time DESC) AS RN
FROM dbo.YourTable)
SELECT Account_ID,
Note_Entry_Dt_Time
FROM CTE
WHERE RN = 2;
Of course, if an ACCOUNT_ID only has 1 row, then it will not be returned in the result set.
The OP's statement "The row will not always be 2." from the comments conflicts with their statement "I am attempting to pull the second latest NOTE_ENTRY_DT_TIME" in the question. At a best guess, this means that the OP has rows with the same date, that could be the "latest" date. If so, then would simply need to replace ROW_NUMBER with DENSE_RANK. Their sampple data, however, doesn't suggest this is the case.
You can use window functions:
select *
from (
select
n.*,
row_number() over(partition by account_id order by note_entry_dt_time desc) rn
from notes n
) t
where rn = 2
I have a table that, for the most part, is individual users. Occasionally there is a joint user. For a joint user, all the fields in the table will be exactly the same as the primary user except for a b-score field. I want to only display one row of data per account, and use the highest b-score to decide which row to use when it is a joint account (so the highest score is displayed only)
I thought it would be a simple
SELECT DISTINCT accountNo, MAX(bscore) FROM table, GROUP BY accountNo
but I'm still getting multiple rows for joints
You seem to want the ANSI-standard row_number() function:
select t.*
from (select t.*, row_number() over (partition by accountNo order by bscore desc) as seqnum
from t
) t
where seqnum = 1;
This worked for me, maybe not the most efficient. Correlated sub-query. The key part is accountNo = a.accountNo.
SELECT DISTINCT a.accountNo, (SELECT MAX(bscore) FROM table WHERE accountNo =
a.accountNo) bscore
FROM table a
GROUP BY a.accountNo
I need to get the Top 10 results for each Region, Market and Name along with those with highest counts (Gaps). There are 4 Regions with 1 to N Markets. I can get the Top 10 but cannot figure out how to do this without using a Union for every Market. Any ideas on how do this?
SELECT DISTINCT TOP 10
Region, Market, Name, Gaps
FROM
TableName
ORDER BY
Region, Market, Gaps DESC
One approach would be to use a CTE (Common Table Expression) if you're on SQL Server 2005 and newer (you aren't specific enough in that regard).
With this CTE, you can partition your data by some criteria - i.e. your Region, Market, Name - and have SQL Server number all your rows starting at 1 for each of those "partitions", ordered by some criteria.
So try something like this:
;WITH RegionsMarkets AS
(
SELECT
Region, Market, Name, Gaps,
RN = ROW_NUMBER() OVER(PARTITION BY Region, Market, Name ORDER BY Gaps DESC)
FROM
dbo.TableName
)
SELECT
Region, Market, Name, Gaps
FROM
RegionsMarkets
WHERE
RN <= 10
Here, I am selecting only the "first" entry for each "partition" (i.e. for each Region, Market, Name tuple) - ordered by Gaps in a descending fashion.
With this, you get the top 10 rows for each (Region, Market, Name) tuple - does that approach what you're looking for??
I think you want row_number():
select t.*
from (select t.*,
row_number() over (partition by region, market order by gaps desc) as seqnum
from tablename t
) t
where seqnum <= 10;
I am not sure if you want name in the partition by clause. If you have more than one name within a market, that may be what you are looking for. (Hint: Sample data and desired results can really help clarify a question.)
I'm looking to pull the top 10% of a summed value on a Postgres sever.
So i'm summing a value with sum(transaction.value) and i'd like the top 10% of the value
From what I gather in your comments, I assume you want to:
Sum transactions per customer to get a total per customer.
List the top 10 % of customers who actually have transactions and spent the most.
WITH cte AS (
SELECT t.customer_id, sum(t.value) AS sum_value
FROM transaction t
GROUP BY 1
)
SELECT *, rank() OVER (ORDER BY sum_value DESC) AS sails_rank
FROM cte
ORDER BY sum_value DESC
LIMIT (SELECT count(*)/10 FROM cte)
Major points
Best to use a CTE here, makes the count cheaper.
The JOIN between customer and transaction automatically excludes customers without transaction. I am assuming relational integrity here (fk constraint on customer_id).
Dividing bigint / int effectively truncates the result (round down to the nearest integer). You may be interested in this related question:
PostgreSQL equivalent for TOP n WITH TIES: LIMIT "with ties"?
I added a sails_rank column which you didn't ask for, but seems to fit your requirement.
As you can see, I didn't even include the table customer in the query. Assuming you have a foreign key constraint on customer_id, that would be redundant (and slower). If you want additional columns from customer in the result, join customer to the result of above query:
WITH cte AS (
SELECT t.customer_id, sum(t.value) AS sum_value
FROM transaction t
GROUP BY 1
)
SELECT c.customer_id, c.name, sub.sum_value, sub.sails_rank
FROM (
SELECT *, rank() OVER (ORDER BY sum_value DESC) AS sails_rank
FROM cte
ORDER BY sum_value DESC
LIMIT (SELECT count(*)/10 FROM cte)
) sub
JOIN customer c USING (customer_id);
I want to use the ROW_NUMBER() to get...
To get the max(ROW_NUMBER()) --> Or i guess this would also be the count of all rows
I tried doing:
SELECT max(ROW_NUMBER() OVER(ORDER BY UserId)) FROM Users
but it didn't seem to work...
To get ROW_NUMBER() using a given piece of information, ie. if I have a name and I want to know what row the name came from.
I assume it would be something similar to what I tried for #1
SELECT ROW_NUMBER() OVER(ORDER BY UserId) From Users WHERE UserName='Joe'
but this didn't work either...
Any Ideas?
For the first question, why not just use?
SELECT COUNT(*) FROM myTable
to get the count.
And for the second question, the primary key of the row is what should be used to identify a particular row. Don't try and use the row number for that.
If you returned Row_Number() in your main query,
SELECT ROW_NUMBER() OVER (Order by Id) AS RowNumber, Field1, Field2, Field3
FROM User
Then when you want to go 5 rows back then you can take the current row number and use the following query to determine the row with currentrow -5
SELECT us.Id
FROM (SELECT ROW_NUMBER() OVER (ORDER BY id) AS Row, Id
FROM User ) us
WHERE Row = CurrentRow - 5
Though I agree with others that you could use count() to get the total number of rows, here is how you can use the row_count():
To get the total no of rows:
with temp as (
select row_number() over (order by id) as rownum
from table_name
)
select max(rownum) from temp
To get the row numbers where name is Matt:
with temp as (
select name, row_number() over (order by id) as rownum
from table_name
)
select rownum from temp where name like 'Matt'
You can further use min(rownum) or max(rownum) to get the first or last row for Matt respectively.
These were very simple implementations of row_number(). You can use it for more complex grouping. Check out my response on Advanced grouping without using a sub query
If you need to return the table's total row count, you can use an alternative way to the SELECT COUNT(*) statement.
Because SELECT COUNT(*) makes a full table scan to return the row count, it can take very long time for a large table. You can use the sysindexes system table instead in this case. There is a ROWS column that contains the total row count for each table in your database. You can use the following select statement:
SELECT rows FROM sysindexes WHERE id = OBJECT_ID('table_name') AND indid < 2
This will drastically reduce the time your query takes.
You can use this for get first record where has clause
SELECT TOP(1) * , ROW_NUMBER() OVER(ORDER BY UserId) AS rownum
FROM Users
WHERE UserName = 'Joe'
ORDER BY rownum ASC
ROW_NUMBER() returns a unique number for each row starting with 1. You can easily use this by simply writing:
ROW_NUMBER() OVER (ORDER BY 'Column_Name' DESC) as ROW_NUMBER
May not be related to the question here. But I found it could be useful when using ROW_NUMBER -
SELECT *,
ROW_NUMBER() OVER (ORDER BY (SELECT 100)) AS Any_ID
FROM #Any_Table
select
Ml.Hid,
ml.blockid,
row_number() over (partition by ml.blockid order by Ml.Hid desc) as rownumber,
H.HNAME
from MIT_LeadBechmarkHamletwise ML
join [MT.HAMLE] h on ML.Hid=h.HID
SELECT num, UserName FROM
(SELECT UserName, ROW_NUMBER() OVER(ORDER BY UserId) AS num
From Users) AS numbered
WHERE UserName='Joe'
You can use Row_Number for limit query result.
Example:
SELECT * FROM (
select row_number() OVER (order by createtime desc) AS ROWINDEX,*
from TABLENAME ) TB
WHERE TB.ROWINDEX between 0 and 10
--
With above query, I will get PAGE 1 of results from TABLENAME.
If you absolutely want to use ROW_NUMBER for this (instead of count(*)) you can always use:
SELECT TOP 1 ROW_NUMBER() OVER (ORDER BY Id)
FROM USERS
ORDER BY ROW_NUMBER() OVER (ORDER BY Id) DESC
Need to create virtual table by using WITH table AS, which is mention in given Query.
By using this virtual table, you can perform CRUD operation w.r.t row_number.
QUERY:
WITH table AS
-
(SELECT row_number() OVER(ORDER BY UserId) rn, * FROM Users)
-
SELECT * FROM table WHERE UserName='Joe'
-
You can use INSERT, UPDATE or DELETE in last sentence by in spite of SELECT.
SQL Row_Number() function is to sort and assign an order number to data rows in related record set. So it is used to number rows, for example to identify the top 10 rows which have the highest order amount or identify the order of each customer which is the highest amount, etc.
If you want to sort the dataset and number each row by seperating them into categories we use Row_Number() with Partition By clause. For example, sorting orders of each customer within itself where the dataset contains all orders, etc.
SELECT
SalesOrderNumber,
CustomerId,
SubTotal,
ROW_NUMBER() OVER (PARTITION BY CustomerId ORDER BY SubTotal DESC) rn
FROM Sales.SalesOrderHeader
But as I understand you want to calculate the number of rows of grouped by a column. To visualize the requirement, if you want to see the count of all orders of the related customer as a seperate column besides order info, you can use COUNT() aggregation function with Partition By clause
For example,
SELECT
SalesOrderNumber,
CustomerId,
COUNT(*) OVER (PARTITION BY CustomerId) CustomerOrderCount
FROM Sales.SalesOrderHeader
This query:
SELECT ROW_NUMBER() OVER(ORDER BY UserId) From Users WHERE UserName='Joe'
will return all rows where the UserName is 'Joe' UNLESS you have no UserName='Joe'
They will be listed in order of UserID and the row_number field will start with 1 and increment however many rows contain UserName='Joe'
If it does not work for you then your WHERE command has an issue OR there is no UserID in the table. Check spelling for both fields UserID and UserName.