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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618 views

Group by without temporary table and filesort

My aim is to make the following query faster. SELECT SQL_NO_CACHE Links.id,Links.link,sum(ID_Links_Words.count) AS wordCount FROM Links LEFT JOIN ID_Links_Words ON Links.id = ID_Links_Words.link ...
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1answer
365 views

Grouping() equivalent in PostgreSQL?

I have a SQL query that runs in MS SQL Server and it has grouping(), rank() and rollup() functions / keywords in it. The query is given below. How can this be translated to PostgreSQL? select top ...
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2answers
434 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
108 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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41 views

Adding counts inside a COALESCE

So I have a continuation of this question. New requirements have thrown in a third table. So here's the breakdown of how the tables relate: TabA(TabA_id, desc) TabB(TabB_id, TabA_id) TabC(TabC_id, ...
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216 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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27 views

Adding a column to aggregated data where new value only applies to a subset of the aggregation

Having trouble explaining this. I have a table like this: Label | Value A | 3 B | 1 C | 4 And another like this: Label | Value | ID A | 1 | ID1 A | 1 | ID2 C ...
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2answers
4k views

Return counts for multiple ranges in a single SELECT statement

I have a Postgres database table foo that, among other things, has a column for score that ranges from 0 - 10. I want a query to return the total number of scores, the number of scores between 0 and 3,...
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1k 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 time,...
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529 views

SQL Server's aggregate functions ignore nulls. How do I correct this?

According to MS's knowledgebase, Except for COUNT, aggregate functions ignore null values. Does anyone know how I can get it to work correctly, that is, return a null if it attempts to ...
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1answer
176 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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304 views

Saving String as unique number in Mongo

I have a field in my collection which is a String in nature. When i run aggregation for this field in data it takes considerable time in aggregation. Total 6 million records are in collection which ...
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227 views

HAVING ANY in Postgres

I'm looking for the right syntax to filter groups (i.e. groups of rows that have been GROUP BY'd) where at least one row fits a certain condition. For example if I wanted to select a group where at ...
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2answers
537 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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284 views

index of aggregate value with fast update?

Is it possible for me to index the sum of a particular table column, such that future lookups will not have to scan the entire table? This table will grow to be very large and a sum of the entire ...
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3answers
5k 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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1answer
55 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, COUNT(...
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1answer
8k views

Postgres error [column must appear in the GROUP BY clause or be used in an aggregate function] when sub query is used

I have two tables employee and phones. An employee can have 0 to n phone numbers. I want to list the employee names with their phone numbers. I am using the below query which runs fine. SELECT ...
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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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2answers
85 views

Selecting minimum value in top grouping only

I have a query built in Oracle 10 which produces a set of data like this: EMP_ID WORK_DT TIME_TYPE ---------- --------- --------- 12345 19-DEC-14 10 12345 18-DEC-14 10 ...
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2answers
382 views

Aggregating sum day by day from multiple joins returns unexpected results

I'm trying to make a table where the task hours and group hours are aggregated day by day. I'm able to get the wanted result for both tasks and groups, but when I try to get them in the same query, I ...
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0answers
295 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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3answers
3k views

Return total number of rows and selected (aggregated) data

I have a function which is selecting some data from a table. I would like to return the selected data and the total number of rows in that table. How can I do that or how can I get the same result in ...
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1answer
666 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
2k 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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1answer
1k 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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232 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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1answer
164 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
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 ...
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1answer
102 views

SQL - Add column if match else, on aggregate data

I have an order table that roughly looks like this |Customer id |Date | revGBP |orderID |GiftOrder | --------------------------------------------------------------------- |1 |1-...
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1answer
112 views

ORA-00937 when calculating a sub-value in an aggregate select statement

The problem described below applies to Oracle 11g databases. I also tested the statements on MySQL and PostgreSQL with no problems of the kind mentioned in this question. I want to use an aggregate-...
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3answers
142 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 ('bar'),...
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3answers
308 views

Can I perform a MAX over a pair of columns?

I would like to execute the following: SELECT person, MAX( (date, priority) ) FROM table GROUP BY person; It would return a person, date and priority row for each distinct value in the person ...
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1answer
451 views

How do I get to this query? SQL Server

I have a database schema : member(memb_no, name, age) book(isbn, title, authors, publisher) borrowed(memb_no, isbn, date) This is the question: For each publisher, print the names of ...
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1answer
305 views

Slow running aggregate of aggregate query

I am looking for the total balance for all accounts that had a negative balance as of a specific point in time. I've already got the code below, and it works, but works horribly. The transactions ...
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2answers
482 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 2+...
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1answer
806 views

Sum of two columns from pivot

I have the following query: DECLARE @columns NVARCHAR(MAX),@columns1 NVARCHAR(MAX), @sql NVARCHAR(MAX),@columns2 NVARCHAR(MAX),@columns3 NVARCHAR(MAX); SET @columns = '1,2,3,4'; SELECT @columns1 = ...
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351 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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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
3k views

PostgreSQL Division In Query Not Working

So I am having a really off day or something, but for the life of me I can not figure this out. I am trying to divide tier1 by total to get a percentage of the total. I thought like this: (tier1 / ...
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2answers
191 views

sqlite group_concat error while executing query

I have table: CREATE TABLE www ( Col_1 VARCHAR, Col_2 VARCHAR ); select count(*) from www; --1496 And I have error: "Error while executing query: aggregate function are not allowed in ...
2
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1answer
814 views

Calculating a running balance to store with transactions

I need to put a read-only copy of balance and transaction data from a legacy system, which will only be used to view/print statements. Balance | id | member_id | product_id | balance | | 1 | ...
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181 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 ...
2
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3answers
9k views

Why MAX() of SUM() giving wrong output?

I have a table employee id name salary city 1 ram 50000 c1 2 sham 20000 c2 3 jadu 80000 c1 4 madhu 90000 c4 5 hari 10000 c2 6 gopal 34000 c3 7 ...
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3answers
814 views

Rolling count of total transactions over time

I need to get a set of total transactions over time on a weekly interval. Essentially I need a total-transactions-to-date column. When I group by WEEK(Date) I get the amount of transactions for that ...
0
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1answer
568 views

PL/SQL group orders by date and sum the total [closed]

I need to group orders by date and sum the total, My table looks like this : TEST_DATE TEST_ID - NUMBER SUCC_ID - NUMBER I need to group by date and sum the total, this is my query: SELECT COUNT(*...
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31 views

Order by Like Value and Count

My Name field values are "Name1 (AB)", "Name2 (AB)", "Name3 (CD)", "Name4 (EF)", etc. Is it possible to count the total "%(AB)" and the total "%(CD)" etc...in one query or will it require a sub query? ...
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1answer
675 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
46 views

assign selected columns to a variable

Select sum(column_a) as a, sum(column_b) as b round(a / b) From table Group by column In the example above I am summing two column, and I would like to use those 2 results in calculating ...
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1answer
2k views

group by clause without aggregate function

I've always assumed GROUP BY was designed specifically for aggregate functions and in all other circumstances you should use ORDER BY. For example, we have three tables: orders, shippers, and ...