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Questions tagged [top-n]

322 questions
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3 answers

Stored Procedure Maximum Pattern Match

This is my stored procedure in Oracle: CREATE OR REPLACE PROCEDURE execute_cproc ( callnum IN VARCHAR2 , RESULT OUT VARCHAR2) AS vara_val NUMBER; varb_val NUMBER; BEGIN SELECT a_val, b_val …
VJS
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3 answers

Query to get top product gainers by sales over previous week

I have a database table with three columns. WeekNumber, ProductName, SalesCount Sample data is shown in below table. I want top 10 gainers(by %) for week 26 over previous week i.e. week 25. The only condition is that the product should have sales…
milan m
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5 answers

How to find the employee with the second highest salary?

Is there any predefined function or method available to get the second highest salary from an employee table?
Anil
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4
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3 answers

MSSQL Get max value from multiple columns by an ID

I've come across many similar posts on this but none I've found got this specific. Here's my sample data: ID CID NARID NATID NADate EID AEDate 1 1655 1 4 12/1/12 202 6/4/14 11:37:01 2 …
versionke
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1 answer

mysql query, how can i get top 5 downloads with GROUP_CONCAT

the following data in MySql table. brand_id|image_id|downloads --------|--------|--------- 8 |9 |8 35 |2829 |4 28 |2960 |3 28 |2961 |3 28 |3041 |3 35 |2831 |3 28 |2965 …
Girish
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4
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2 answers

top-N query doing too much work in spite of STOPKEY optimization

This is going to be long, so here's a quick summary to draw you in: my top-N query with COUNT STOPKEY and ORDER BY STOPKEY in its plan is still slow for no good reason. Now, the details. It starts with a slow function. In real life it involves…
user2404501
3
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0 answers

Top n loudest audio packet forwarding from media in a conference

I have an SFU media which just relays audio packets to everyone except the sender. Now for a large-scale conference, it is not a good idea to send all participant's audio packets to everyone if the participant count goes beyond 50-100 (let's assume…
Nafiul Alam Fuji
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1 answer

select top n values by group with n depending on other value in data frame

I'm quite new to r and coding in general. Your help would be highly appreciated :) I'm trying to select the top n values by group with n depending on an other value (in the following called factor) from my data frame. Then, the selected values shoud…
kate99
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2 answers

PyTorch: Zero all elements of vector except top k?

I am trying to create a new activation layer, let’s call it topk, that would work as follows. It will take a vector x of size n as input (result of multiplying previous layer output by weight matrix and adding bias) and a positive integer k and…
user40739
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1 answer

How to extract the first n rows per group from a Spark data frame using recent versions of dplyr (1.0), sparklyr (1.4) and SPARK (3.0) / Hadoop (2.7)?

My attempts with top_n() and scale_head() both failed with errors. An issue with top_n() was reported in https://github.com/tidyverse/dplyr/issues/4467 and closed by Hadley with the comment: This will be resolved by #4687 + tidyverse/dbplyr#394…
jimbod119
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2 answers

dplyr - How to filter the top n groups with more (sum) sales?

I am using dplyr on R and I am trying to filter a tibble which contains transactional data. The columns of my interest are "Country" and "Sales". I have a lot of countries and for exploration purposes I want to analyze only the TOP 5 countries with…
spcvalente
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2 answers

PostgreSQL query rows with least null value on columns

How can I query rows where the output would be the rows with least null value on the columns? My data is: ID | col1 | col2 | col3 | col4 -----------+----------+-----------+-----------+----------- 1 | Null …
gdmplt
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SQL How to return the record with the most recent date and also highest int value

I have to return the most recent row in a SQL database, grouped by CallID. The 'most recent' in this instance means the most recent DepartureDate and the highest Departuretime (int) on that date. See below example for your reference: set dateformat…
Naz
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3
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3 answers

Select the n most frequent values in a variable

I would like to find the most common values in a column in a data frame. I assume using table would be the best way to do this? I then want to filter/subset my data frame to only include these top-n values. An example of my data frame is as follows.…
Fiona
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1 answer

top_n() not selecting n

Aim: To plot the first 20 countries in descending order Problem: When using the top_n function, it insists in selecting all and not just the top 20. Here is my code: #Omit missing values na.omit(kiva_loans)%>% #Group by country label …
delcast
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