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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35 views

Select query for returning different data based on creation time

I have a view, which will Select data from table reports the select will filter the data based on multiple dates. reports table: id, key_id, position, created_at My select: pr.key_id, ...
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1answer
20 views

nesting MAX for SELECT

I have a table, containing TV series episodes: series: | series_id | season | episode | title | 1 | 1 | 18 | xxx | 1 | 2 | 3 | xxy | 3 | ...
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1answer
50 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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1answer
72 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 ...
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2answers
63 views

compare dates in results

I'm looking to compare the dates in the result set Example: SELECT * FROM tbl WHERE foo=bar Output id, datetime, name 1, 2014-01-01 18:13:45, test 1 2, 2014-01-01 19:01:32, test 2 3, 2014-01-01 ...
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1answer
65 views

Nested query not recognize external table

i need to a query that show week by week the total amount of imports of any company and in addition add a ranking position depending on that amount. I've made this query but the problem is the inner ...
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1answer
88 views

How can I use running total aggregates in a query to output financial accumulations?

I am attempting to write a query that will be consumed by a SSRS 2012 report. Given a paid invoice, with a certain set of account allocations towards which the money paid towards it must be saved, I ...
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0answers
42 views

MySQL aggregation count performance

I have a table with about 30 million records, and I'm doing a query where I can group by field Year and count the results for that year. The table structure looks like: id | year | amount The ...
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4answers
122 views

Use of HAVING without GROUP BY in SQL queries

In order to use HAVING in SQL queries , must there be a GROUP BY to aggregate the column names? Are there any special cases where it is possible to use HAVING without a GROUP BY in SQL queries? ...
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2answers
103 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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1answer
108 views

How to get MySQL to iterate a subquery in an aggregate select?

Because the vocabulary describing what I'd like to do can be so disparate, I haven't had any luck figuring out why MySQL 5.6 is doing what it does. Consider the following two simple queries: #1 ...
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1answer
70 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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1answer
80 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
49 views

How to add up a column depending on data from another column

I have a table which has results and a table that has band_name and band_id. Now I need to create a query which will add up the total points for each band and display the band name and ID, so far I ...
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1answer
57 views

What is the appropriate SQL method for “Safe to SUM”?

In SQL Server 2008 R2+ we, unfortunately, have some nvarchar columns storing numeric data. In some cases we want to SUM the data when it can be summed. The problem is that ISNUMERIC() returns 1 for a ...
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1answer
66 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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0answers
73 views

Select the top N products from each category, but where the merchant hasn't already been picked

this isn't the usual Select top N results from each category question - there's a little bit more to it. I have the Select top N query as follows: SELECT tmp.id, tmp.name, tmp.category_id, ...
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3answers
113 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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2answers
108 views

Query to return fields of distinct values per key

In the process of building a data warehouse we are creating some aggregation tables for a reporting engine. We would like to build a single aggregation table from the fact table that can exist as list ...
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1answer
207 views

Column 'Comments.Text' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause

They have explained the root of the problem very well and even advised to use max aggregate as a solution. But, lets take the example group_id item_id comment -------------------------------- ...
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1answer
117 views

Index for ORDER BY on aggregate in MySQL

I'm working with the following query: SELECT *, SUM(entries_count) AS entries_count FROM leads WHERE promo_id IN (1, 2, 3) GROUP BY user_id ORDER BY entries_count DESC LIMIT 25 OFFSET 100; It's ...
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1answer
506 views

How do I get the aggregate of a window function in Postgres?

I have a table containing a two columns of permutations/combinations of integer arrays, and a third column containing a value, like so: CREATE TABLE foo ( perm integer[] NOT NULL, combo integer[] ...
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1answer
150 views

Is it possible to reduce a group to a row based on some criteria?

I'd like to perform a select on a table involving a GROUP BY such that all rows that share the same set of identifiers are grouped together, but I want to reduce the group to one of the grouped rows ...
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2answers
968 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
574 views

How can I write windowing query which sums a column to create discrete buckets?

I have a table which includes a column of decimal values, such as this: id value size -- ----- ---- 1 100 .02 2 99 .38 3 98 .13 4 97 .35 5 96 .15 6 95 .57 7 94 .25 ...
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3answers
192 views

Is using SUM() twice suboptimal?

I know I have to write SUM twice, if I wish to use it in a HAVING clause (or use a derived table otherwise): SELECT id, sum(hours) AS totalhours FROM mytable GROUP BY id HAVING sum(hours) ...
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200 views

How to improve the performance for SQL Server Count(distinct()) and Sum() functions? [closed]

The below one is my query. It's taking 12 seconds for the execution process. The count(distinct()) and SUM() functions are taking long time for execution. I tried it after create the non-cluster index ...
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1answer
115 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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1answer
1k views

Select first row (grouping) + add aggregate function

First have a look at this question on StackOverflow. I'm looking to accomplish the same task, except I also need to add an aggregate function (PostGIS's ST_Union) to my query. How can I combine the ...
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0answers
271 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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1answer
106 views

Aggregating statistics from child rows

I have a parent row and then many child rows, and I must aggregate statistics from these child rows. For a more concrete example let's imagine I have one round of golf (parent row) and then child ...
7
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1answer
106 views

Trouble with SQL and aggregates

With this query: SELECT SUM(qty) AS sumQty, cnetprodid FROM quoteitem WHERE ordered = 1 AND sageSOPOrderReturnLineID IS NOT NULL AND LEN(LTRIM(RTRIM(cnetprodid))) > 0 ...
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320 views

What is the correct result for this query?

I came across this puzzle in the comments here CREATE TABLE r (b INT); SELECT 1 FROM r HAVING 1=1; SQL Server and PostgreSQL return 1 row. MySQL and Oracle return zero rows. Which is correct? ...
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1answer
126 views

Group activities in activity feed by users and products

On my website I'm building an activity feed where I got the basics done and are now making some improvements here and there. One of them is the grouping. I've built it so that if multiple users buys ...
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1answer
71 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 ...
5
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1answer
624 views

Oracle aggregate functions slows query down massively

I have a table with ~12M rows of data in it. Here is the table structure: SYSTEM_ID BATCH_ID MEASUREMENT_INDEX, PARAMETER_ONE, PARAMETER_TWO The primary key is made up of the first three columns. I ...
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2answers
2k views

how to calculate difference of first row and last row fields value in each group

I have table with structure like this: +-------+------------------+ | Value | Date | +-------+------------------+ | 10 | 10/10/2010 10:00 | | 11 | 10/10/2010 10:15 | | 15 | ...
5
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3answers
368 views

Many-to-Too-Many Relationship

I'm working on a book database. And among others, I have the following two tables (a bit simplified for the question): tblBook: ID, Title tblPerson: ID, Name Note that the tblPerson table contains ...
3
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1answer
241 views

How to represent aggregates in a data warehouse

I am building the dimensional model for a data warehouse (as an exercise for a mini-course I am doing) and I want to build an aggregate to speed up queries. Basically, I want the aggregate to group ...
4
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1answer
112 views

GROUP BY on a dependent field

Let's say I have a SELECT statement as follows: SELECT ..., field1 FROM ... GROUP BY field1 Now let's say I want to return a second field, field2. As it happens, field2 is functionally dependent ...
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2answers
86 views

Grouping data checking against top values

I've got data in this form: CallNum Value Accepted -------------------------------------- 971374 81.482204444473609 True 971374 83.783551111089764 False 971374 97.936875555547886 ...
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1answer
421 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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3answers
2k views

Why does ANSI SQL define SUM(no rows) as NULL?

The ANSI SQL standard defines (chapter 6.5, set function specification) the following behaviour for aggregate functions on empty result sets: COUNT(...) = 0 AVG(...) = NULL MIN(...) = NULL MAX(...) = ...
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2answers
308 views

Pivoting data for stacked charts (grouping and creating new columns for each distinct value)?

I have something that looks like this (SQL Fiddle here): Date Location Value 1/1/2012 Baltimore 36 1/1/2012 Houston 36 1/1/2012 Chicago 55 2/1/2012 Baltimore 49 ...
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1answer
338 views

Is it possible to wrap aggregate functions in Postgres?

Postgres' string_agg(expr, delimiter) function is great. But I would like to have a version that takes a single argument -- the field to aggregate -- and assumes a delimiter of ', ' since that is ...
15
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5answers
6k views

What is the most efficient way to get the minimum of multiple columns on SQL Server 2005?

I'm in a situation where I want to get the minimum value from of 6 columns. I've found three ways so far to accomplish this, but I have concerns with the performance of these methods and would like ...
2
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1answer
170 views

Is it possible to make a reference to the result of an aggregate function in a SELECT clause from the same SELECT clause?

I'm not a Database Administrator--just a Software Engineer. I would like to know if it is possible to reduce the following T-SQL query: SELECT SUM(Price * Quantity) as 'Total', SUM(Price * ...
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2answers
1k views

How do I create a user-defined aggregate function?

I need an aggregate function that MySQL doesn't provide. I would like it to be in MySQL's flavor of SQL (that is, not in C). How do I do this? What I'm stuck on is creating an aggregate function -- ...
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3answers
3k views

Why is an aggregate query significantly faster with a GROUP BY clause than without one?

I'm just curious why an aggregate query runs so much faster with a GROUP BY clause than without one. For example, this query takes almost 10 seconds to run SELECT MIN(CreatedDate) FROM MyTable WHERE ...
2
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1answer
577 views

Why use custom CLR aggregate functions for string concatenation and geometry unions in SQL Server?

I often need to do string concatenation or geometry unions over a column in SQL Server 2008 and I'm aware that you can write custom aggregate functions in .NET and register them with SQL Server to do ...