Why prefer composition instead of inheritance? What trade-offs are there for each approach? And the converse question: when should I choose inheritance instead of composition?

I'm trying to aggregate some rows in my dataframe with a list[str] column. For each id I need the intersection of all the lists in the group. Not sure if I'm just overthinking it but I can't provid...

I am learning elastic search and would like to count distinct values. So far I can count values but not distinct. Here is the sample data: curl http://localhost:9200/store/item/ -XPOST -d '{ "Re...

I am trying to accomplish the following in MySQL (see pseudo code) SELECT DISTINCT gid FROM `gd` WHERE COUNT(*) > 10 ORDER BY lastupdated DESC Is there a way to do this without using a (SELEC...

Basically, I am trying the following: SELECT m.col1, SUM(SELECT col5 FROM table WHERE col2 = m.col1) FROM table AS m This doesn't seem to work. Is there any solution?

What is the difference between association, aggregation, and composition? Please explain in terms of implementation.

If you're doing min/max/avg queries, do you prefer to use aggregation tables or simply query across a range of rows in the raw table? This is obviously a very open-ended question and there's no on...

I have a User model and I want to perform generic aggregation. mean any array of object I pass to this function it executes. this is the sample of getUser function public async getUser(aggregate: o...

horrible title, but let me explain: i've got this django model containing a timestamp (date) and the attribute to log - f.e. the number of users consuming some ressource - (value). class Viewers(m...

I got a large amount of data in Elasticsearch. My douments have a nested field called "records" that contains a list of objects with several fields. I want to be able to query specific objects fro...

I'm having trouble reading documents from MongoDB using the aggregation framework: I always get null IDs in my results. This only happens for documents that have composite IDs. I tried various vers...

i want to convert this sql query to elastic DSL query language SELECT t.pk_c_c_s, t.fk_c_c_id, t.s_b_a, t.datetime, SUBSTR(t.datetime, 0, 7) m, ( SELECT SUM(i.s_b_a) sarpu FROM TBL_C_C_S i...

I have a Pandas data frame like this: test = pd.DataFrame({ 'Date' : ['2016-04-01','2016-04-01','2016-04-02', '2016-04-02','2016-04-03','2016-04-04', '2016-04-05','2016-04-06','2016-04-06'], 'U...

TL;DR I can't figure out how to write a recursive Postgres query that doesn't use aggregate functions in its recursive part. Is there an alternative way to write the recursive query shown below? L...

I am looking at the following documentation. The following inserts documents into a collection classes. db.classes.insertMany( [ { _id: 1, title: "Reading is ...", enrollmentlist: [ &quo...

I have a collection of ProductViews: { productId: "5b8c0f3204a10228b00a1745", createdAt: "2018-09-07T17:18:40.759Z" } And I have a query for fetching the daily views for a sp...

can you help me please how to properly use aggregate function in R? I have data like this: SPORT FLOWS [1,] "Other" "1" [2,] "Other" "1" [3,] "Other" "1" [4,] "Other" "1" [5,] "Other2" "1" [6...

MongoDB has recently added an option to perform an update operation by providing an aggregation pipeline rather than the standard modifier object. Check MongoDB's docs on this topic. The ability to...

I have a list of values paid and want to display the total paid. I have used aggregation and Sum to calculate the values together. The problem is,I just want the total value printed out, but aggreg...

How I achieve a one-to-one relationship using Typeform MongoDB. I m trying to join two documents using aggregation but not achieve success. Please provide one solution. Entity details 1.counrty ...

I want to implement Single Responsibility principle in my projects Domain layer (Clean MVVM). I've approximately 200 different use-cases which are being very hectic to manage. Now I'm thinking to c...

I'm trying to do this for days, but can't find any success I'm using MongoDB, and I tried to do it with many pipeline steps but I couldn't find a way. I have a players collection, each player conta...

During internet searching I see lot of questions now to disable ONLY_FULL_GROUP_BY feature, so it mean lot of developers have a trouble with writing SQL queries in this strict mode. I know it prett...

This is my transaction data. It shows the transactions made from the accounts in from column to the accounts in to column with the date and the amount information data id from to date amount &lt...

I'm using a pandas DataFrame in which one column contains numpy arrays. When trying to sum that column via aggregation I get an error stating 'Must produce aggregated value'. e.g. import pandas ...