Combining multiple data points into a single data point. This usually is used in reference to SQL and usually to an aggregate function of some sort.

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Query on bridge table

I have three tables dealing with books: Authors, Titles of books written and a bridge table TitleAuthor, from from which I am trying to find all books (Titles) with more than one author. These are the ...
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63 views

Name for intermediate aggregated data [closed]

We have raw data and aggregated data as well as sometimes multiple levels of aggregation between. Is there a name for the data in that intermediate "state" of aggregation? Just like how we have Real ...
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599 views

Postgres Index a query with MAX and groupBy

Is there any way to index the following query? SELECT run_id, MAX ( frame ) , MAX ( time ) FROM run.frames_stat GROUP BY run_id; I've tried creating sorted (non-composite) indexes on frame and ...
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136 views

How group by affects aggregate functions

I tried to understand the following scenarios: Table name: family +------+-------+ | id | name | +------+-------+ | 1 | alice | | 2 | bob | +------+-------+ That table will be used for ...
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245 views

How to include in the result of a `SELECT … GROUP BY …` all the other columns that are functionally dependent on the grouping ones?

I'll base this question on a toy example. Let this be table A: A ------------------------- U | V | W | X | Y | Z ------------------------- a | b | c | 1 | 6 | 8.3 a | b | c | 1 | 4 | ...
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236 views

Aggregate function / query in Oracle 11g

I am working in Oracle 11g. I have been racking my brain all day trying to figure out how to write a particular SQL statement (am a Java/.NET Developer, would not consider myself a SQL expert) I ...
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44 views

Aggregating on a repeated group

In a current report, I'm trying to track the migration of a person from department n, to n+1, or to n+k. My data is split into a row per term (university data). An example: dept | term ...
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38 views

Aggregate rows of type array

I need to aggregate rows with a single column of type INT[] into a single array of type INT[]. The following results in an error "could not find array type for data type integer[]": create temp ...
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54 views

Oracle How to Generate Multiple Ranges Based on a Result Set

Given a table like this: with qtys as ( select 3 as qty from dual union all select 10 as qty from dual union all select 9 as qty from dual union all select 7 as qty from dual union all ...
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68 views

How to use PostgreSQL bit_or function to aggregate column?

I wish to use PostgreSQL's bit_or function on several rows of a single column of my table, but I can't figure out the proper usage for this. Suppose I have bitwise flags in my column flags, and the ...
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75 views

Count of distinct values of a table using sql

name number ============= lin | 8 lin | 8 lin | 8 rob | 8 rob | 8 rob | 8 lin | 8 lin | 41 lin | 41 rob | 41 and I want the result like name | Count of 8 | count of 41 ...
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423 views

How to get the equivalent of array or string GROUP BY aggregate functions in Access?

From SQL Aggregate Functions (Office 2007) there are only these GROUP BY aggregate functions in Access SQL: Count(), Sum(), Avg(), First(), Last(), Min(), Max(), StDev(), StDevP(), Var(), VarP() ...
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Combine results of two queries, where the second relies on the first

I have one query which is returning name(text), total, created_at And another query which is returning the same thing name(text), total, created_at The second query usually is returning more ...
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657 views

Understanding multiple table join with aggregation

I have a basic question on how JOIN works on multiple tables. I want to count occurrences of Foreign Key in link1 & link2 CREATE TABLE main ( id SERIAL PRIMARY KEY, name text NOT NULL ); ...
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1answer
58 views

Writing a view that caches to another table

I have a table market_trades with columns timestamp, market_id, and amount: api_production=# \d market_trades; Table "public.market_trades" Column | ...
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477 views

Fetch data from same table using two group by clauses in mysql

I have one table name as consultant with 4 fields(id, name,user_type, Created date). I need to write an mysql query for return the count of user_type in each month. In my table, user_type is ...
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131 views

Query for frequency of e-mail addresses in a field

Newbie here. I know the answer is out there, but lack the vocabulary to ask the right question... I am looking for a MYSQL query which gives me the frequency of addresses in the field emailaddress. ...
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69 views

Aggregating results of two database views in one database view

I have a view with name of UserInfo like this: And another view with name of UserRoleInfo like this: I want to aggregate all the records of the two views for one user name like H.F into ...
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676 views

Slow queries related to subqueries using aggregation

Here's a simplified version of the queries I am running: select ... from editions join edition_events on edition_events.edition_id = editions.id join events on events.id = ...
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789 views

ORDER BY on aggregate field on a closure table giving unexpected results

I am updating my companies product database and I'm looking into different ways to do design our faceted navigation "selector" tables. The idea of faceted navigation might look like this: It's ...
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46 views

Displaying a value associated with a maximum value

I have a PostgreSQL database for a supermarket (it's a toy problem) and I need to find which outlet has sold the most copies of each product and display it in a query which also shows the product ...
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1answer
31 views

Help to retrieve data set

I have data set as below, for each Parent Record there can be multiple Cancel and Un-Cancels. I am trying to pull for each Parent, I am trying to find when it when it got cancelled and when it got ...
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43 views

postgresql double count query

I have a table with 3 columns: key, status and rank. status contains numbers and rank contains t or f. key is auto numbered and irrelevant here. my goal is to count how many in each status are t and ...
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348 views

SQL query to sum a column prior to date and show all entries after that date

I have a database function that sum a column prior to a date and after that date show all entries one by one. that function return the data ordered by a common field and apply the sum by date every ...
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1answer
141 views

Join and count boolean columns by logical OR

There are two tables: user_table and user_schedule. Each user has four schedule rows (one for each 6 hour period per day) with one column for every workday. The desired result is to count the number ...
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363 views

Calculating percentage from two tables

I have two tables: First one contains unique mentees under one mentor, so mentors can have more than one mentee in that table. Second one contains interactions of mentors with mentees on different ...
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500 views

MongoDB Insert Performance

I have some data which are aggregated in chunks and later pushed into another collection. The problem is that aggregated data pushing to another collection is very slow and takes from few hours and i ...
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1k views

Select only rows with minimum values from union table

SQL Server 2005 Here is a sampling of the data from a union of two tables (named "vProducts_All"): DBID UPC Price1 Price2 1 023614025559 689.0000 649.0000 2 ...
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189 views

Optimizing for data that does not fit in memory

We have a database that contains around 235 GB of data (calculcated using pg_total_relation_size for each table) on a server with around 77GB of memory. The server is used for nothing else (aside from ...
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52 views

Multidimensional aggregates

Suppose one wanted to cache simple aggregate data over a table or grouped parts of a table, one could simply make a table with the aggregated results. If the original table is only appended to, it is ...
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1answer
59 views

Consolidating large table

I need some help with a complex query. Table def: Table "public.agent_log" Column | Type | Modifiers ...
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197 views

Retrieve title from rows with a maximum count in other columns

Given the following table archived: CREATE TABLE archived ( sid serial -- row id showurl text -- can be: btg, tmwwt, gcaf, emda title text reference text -- title id ...
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406 views

Get maximum from aggregated values in a query

I have a table details it has a column kills and a column player_slot and a column match_id. I want to find the maximum difference between the SUM of kills for player_slot 0-4 and 128-132. Can someone ...
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363 views

Aggregating data - Getting data inserted after last time query was run

On a SQL Server 2008 R2 DB, I'm running an aggregation query every hour or so, on data that's being constantly inserted into a table, and what I'd like to do is pull all the "new" records that were ...
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212 views

Mysql: Schema/Query Performance Approach for aggregated mailbox folders

I am about to code a messaging system where users can write messages to other users. User can create custom inbox folders for sorting the messages they receive, however, every user has 2 main inboxes: ...
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114 views

How to aggregate datapoints in a table?

Suppose I have following table - CREATE TABLE data_points (t DATETIME PRIMARY KEY, value INTEGER); I want to aggregate the data by calculating average of every 10 points in the table. i.e. If ...
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1answer
37 views

Extract start and end per group of rows, where only the end can be identified

I have a table that looks like this. id date_from date_to description vehicle 1 2015-10-21 08:00 2015-10-21 10:00 GARAGE TO CLIENT 1 1 2 2015-10-21 12:00 ...
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133 views

Calculating Running Average using Over clause in SQL server

My table looks like this: CREATE TABLE [dbo].[TimeSeries]( [LOCID] [int] NOT NULL, [Date] DateTime, [YEAR] int, [MONTH] tinyint, [RTT] [int] PRIMARY KEY ( [LOCID] ASC,[Date] ASC) ) It contains 12 ...
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59 views

MySQL Get first and last day of multiple records

I have a table HC_RSPI_data: | RADIO_TYPE | HOP | TOWARDS | RSPI | TP_NAME | DATE_TIME_END | TIME_LENGTH | RLTM_min | RLTM_max | ...
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41 views

Best way to perform real time analytics on a growing collection of json file ( very large ) [closed]

I have a very large collection of JSON file (tens of millions) on S3 and I need to have some kind of aggregation (perform continuously as the collection grows). The aggregation is mainly counter ...
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158 views

Optimization for aggregation and grouping with MySQL

I have an application that is pulling data on a daily basis from numerous APIs, storing it and then presenting it on the front end in various charts, tables, etc.. I'm having some issues avoiding ...
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92 views

Combine multiple similar queries into one

I need to calculate a weighted average using the following table. I have to calculate this number for metric_1 up to metric_10. All the metric columns have a value from 1 to 5. ...
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1answer
135 views

Postgres Nested WHEN Aggregate Function

In PostgreSQL (version 9.4) I am trying to construct a query to determine in various tranches how many times various numbers appear in the data set between ranges. When I query group-ing by ...
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1answer
54 views

How to properly aggregate?

I have a table for logs with over 6 million records. I want a query that shows me all the occurrences where the src goes to the same destination/port. I tried this: SELECT src, dst, dstport, ...
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209 views

Pentaho Kettle (Data Intergration) MongoDB Aggregation

I'm using kettle v5.2 which support the aggregation pipleline in MongoDB when using MongoDB input the query works for small data set but I need to use option allowDiskUse to the query can't figure ...
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555 views

Select two aggregate functions on the same column using different criteria - performance

Dear stack exchange users, first question here. The database in question is a service database where a user hires a service. Now I would like to show the person that was hired an overview of how many ...
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173 views

Multischema view for postgres , querying multiple databases

Im managing SaaS app where each customer has a separate database (Postgres 9.3) . I need to figure out the best way to aggregate and query this data ( READ-only ). I know postgres has problems with ...
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115 views

Join and aggregate result and insert blanks for missing appendants

Consider these two simplified tables: CREATE TABLE "sources" ( "id" serial NOT NULL, "name" text NOT NULL, CONSTRAINT "sources_pkey" PRIMARY KEY ("id") ); CREATE TABLE "values" ( ...
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139 views

Type with nested table in oracle

I want to create a type with a nested table. I have a table called assignment_tbl which I want to put a type assignment_status. This assignment_status contains primitive types but also contains a ...
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749 views

How to aggregate pairs of id values into groups

I have a table with two id columns id1 and id2. Each row shows that 2 id values have been linked together. My actual data has both id columns as varchar(20) but I have used integers in the example ...