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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1answer
430 views

MongoDB: Aggregation workaround by helper collection

Since I regularly run against mongodb's document size limit and also aggregation framework's group limitations >16M, depending on the amount of data I need to process, I look for a simple workaround. ...
2
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1answer
724 views

Performing aggregations and calculations: SQL (CTE) vs MDX

I’ve hit a wall and would like some expert advice. I’m building a data warehouse and don’t quite understand whether the calculations (also time aggregations) should be done in SQL (T-SQL and CTE) or ...
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0answers
684 views

How to calculate running total based on dynamic values?

I need to calculate the running total in which the target column is changing along with the time. Its something which aws does. Charging based for only what you use. So how do I aggregate sum of ...
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2answers
9k views

How to select rows which have max and min of count?

I have the following table in SQL Server 2012: CREATE TABLE [MyTable] ( [Id] UNIQUEIDENTIFIER NOT NULL PRIMARY KEY DEFAULT NEWID(), [MyGroup] INT NOT NULL ); I want to output a table of the ...
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4answers
92 views

Getting an aggregate (here: min) for a group of values [closed]

Example table: ID | value A | value B ---------------------- 1 | abc | 3 1 | def | 5 1 | ghi | 1 2 | cba | 9 2 | fed | 4 I want the ...
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3answers
11k views

Select query to retrieve values even if are null

I need some help in a query. Need to retrieve data from 1 table, even if one of the field has null value. Here's an example: Select name, SUM(credit) as credit From expenses Where name like ...
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2answers
916 views

LIMIT to one row per ID

This query gives me multiple hits because of each assetid may contain many vb.title. How can I limit the result to only 1 hit for each assetid? 'select DISTINCT v.id, v.purchasedate, ...
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2answers
368 views

PostgreSQL : avoid SUM over same values multiple times

I've a student table and a table of scores in various subjects. I want to sum score1 & score2 for each student across all subjects and then add the bonus for each student. CREATE TABLE student ( ...
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1answer
2k views

PostgreSQL: How to get a sum of values and the total rows that went into each value? [closed]

I have a table, MyData in the following format: |id|theme_id|priority_id|value| I am trying to get the following result for all the rows: theme_id | priority_id | total | sum ...
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3answers
139 views

Longest matching suffix while using aggregate functions

Background Looking to find the longest matching string suffix. Setup Consider the following fiddle: CREATE TABLE noun ("label" varchar(10)) ; INSERT INTO noun ("label") VALUES ...
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1answer
60 views

MAX of a varchar column

I have a table with a column named price typed as varchar. I want the maximum value of this column. I am using this query: SELECT MAX(price) FROM product_management.`item_list` but the result is ...
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2answers
31 views

Selecting Values That Differ From Section Average

I'm attempting to select data from a table that's already been made containing records of file size as taken every twelve hours. The table looks something like this: surrogate_id | partition_id | ...
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1answer
652 views

Split two rows into two columns

I have the following table: id | name | action | count ------------------------------ 1 | Value1 | 0 | 27 1 | Value1 | 1 | 49 2 | Value2 | 0 | 7 2 | Value2 | 1 | ...
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1answer
31 views

Is it possible to find the user whose aggregated score reaches X value first?

Given this sample fiddle containing sales value and date for two users: http://sqlfiddle.com/#!2/8148be/3 How can I find the first user who has reached a total saleValue of 30 since the beginning of ...
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2answers
37 views

Aggregate function to return any (first) encountered value

How do I tell PostgreSQL to return first encountered value instead of an aggregate column? Table "public.cache" Column | Type | Modifiers | Storage | Stats target | ...
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1answer
18 views

PostgreSQL ntile() partition

i have a point grid with population values. each point has an id and population value. i also have an state_id which say in what state the point is. now i want to calculate the percentile ntile(100) ...
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1answer
40 views

Strategies for reducing data to summaries within a table over time?

I have a large data set where large numbers of entries differ only by timestamp. In the short term it's beneficial to maintain individual entries so that we can correlate by time for individual data ...
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2answers
95 views

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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1answer
65 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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2answers
919 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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1answer
150 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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2answers
413 views

Calculating average with AVG for a list of numbers

This is probably a newbie question (bear with me) but how can I calculate the average for a list of numbers using SQL and the AVG function? I mean, I can add together numbers in SQL like: SELECT ...
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1answer
315 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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2answers
274 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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2answers
48 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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1answer
45 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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1answer
98 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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1answer
122 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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1answer
734 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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2answers
341 views

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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2answers
1k 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
59 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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1answer
624 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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2answers
158 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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1answer
779 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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1answer
843 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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2answers
47 views

An aggregate may not appear in the WHERE clause

I'm attempting to execute the following query to return a data set where the Updated Date is the most recent. I'm thinking my joins are causing the issue, but I'm not sure, and have not made any ...
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1answer
72 views

Group rows by running aggregate

I have a set of transactions that can either be payments or purchases. The purchases can be of different types (e.g. 'ApplePurchase', 'OrangePurchase'). I will select some payments by their coupon ...
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1answer
45 views

Multiple to_json(array_agg), separate joins

I'm building a messaging system, and trying to get a list of messages and their replies; and also join the participants of the message threads. So I'm shooting for messages = [{id, subject, body, ...
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2answers
52 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
32 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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1answer
62 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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1answer
475 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
162 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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2answers
489 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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3answers
4k views

Getting around the constraint “column must appear in the GROUP BY clause or be used in an aggregate function”

I'm using Postgres, which enforces the constraint that all columns in a SELECT...GROUP BY must appear in the GROUP BY clause or be used in an aggregate function. Lets say I'm modelling peoples' cars, ...
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vote
1answer
623 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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3answers
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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2answers
218 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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2answers
57 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 ...