How to use WITH in a better way to parametrise a date
I love to use CTEs to create nice and clear queries. However, I'm pretty sure the query I created is really inefficient.Is there a better way to do this and keep things clear ?with first_date as ( --...
View ArticleClients which have seen an impression of a product at least 3 times before...
or a project I am working on I was asked to solve this task:Given the table**events** event_id int (autoincrement) --10B distinct values event_ts datetime -- 10B event_type int (1 = impression, 2 =...
View ArticleIndex is not used when doing a query with PostgreSQL CTE
Given I use the following table :CREATE TABLE operations ( asset_id varchar(255) NOT NULL, event_id varchar(255) NULL, updated_at timestamptz NOT NULL DEFAULT CURRENT_TIMESTAMP);and the following Index...
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Find best intersect (most elements) between Order (haystack) and Pricerules...
Full disclosureI have posted a greater scoped question at SO a couple of days ago with a bounty (no answers yet).Scope hereHow can a CTE be used to find a match with the most elements?For the order 403...
View ArticleIs it possible to update an existing table in a single statement, using the...
I know I can achieve this in many ways - this is a purely academic question to see if it's possible to do this in a single statement, in order to further my knowledge of SQL.We're splitting an old,...
View ArticleHow to retrieve min/max values and corresponding dates in a table
I'm trying to figure how to retrieve minimum/maximum values and minimum/maximum dates from a data set, but also the date value that corresponds to each minimum/maximum value.Example Data:CREATE TABLE...
View ArticleINSERT result for SELECT FROM join'ed tables just modified
I have the task to insert data into couple tables and return data from their intersection in one query. The tables are linked through specific fields (solditems refers to products and invoices,...
View ArticleCreate JSON object from recursive tree structure
Having this simple many-to-many self-referential structure.An item owns other items through the joins table:CREATE TABLE items ( item_id serial PRIMARY KEY, title text);CREATE TABLE joins ( id serial...
View ArticleCommon Table Expression syntax
Considering a query with CTEs:WITH cte_0 AS ( SELECT SUM(col_0) FROM table_0 WHERE condition_00 AND condition_01 ), cte_1 AS ( SELECT SUM(col_1) FROM table_0 WHERE condition_10 AND condition_11 )...
View ArticleReturn the longest consecutive sequence of a value in specific column
I am using PostgreSQL 12.0 and trying to get the longest sequence of continuous rows for a specific column and value.The table is called team2 and contains a team's results which looks like:match_id...
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How to match rows from relationship via a recursive CTE
Apologies for the terrible question title, I couldn't think how to describe this question in a single line.I have a schema that looks roughly like this:...
View ArticleHelp with CTE syntax in SQL
I am new to SQL, I tried to create a CTE, but I get a red squiggle under the AS and I am getting an error message in the process of executing the syntax:Msg 102, Level 15, State 1, Line 117 Incorrect...
View ArticleUnable to use INSERT within CTE
I am trying to use a CTE to insert some random data into a table -create table foo (id integer)with x as (select random()) insert into foo (id) select x from xThis gives an error:ERROR: column "id" is...
View ArticleHow can I optimize a recursive CTE inside a IVTF?
I have a recursive CTE inside a inline table-valued function. The ITVF is returning a list of IDs containing a long sequence of ancestors for a person, it usually loops back about 12 to 18 times before...
View ArticleWhy is PostgreSQL performing a sequential scan, except when my CTE is...
The issueMy application is encountering performance issues on a query that, to the best of my understanding, should be performant. In this post, I have simplified the query and schema while still...
View ArticleGrouping values into buckets
I'm working a query and I wasn't sure if my current approach is the "best" approach.I got a table filled with values and a table with buckets that I use to group those values.There are 2 types of...
View Articleextracting row level records from query results based on an aggregate...
Given enough time, maybe I could figure this out. I don't have the time to spare,a lot of tasks ahead of me, so I'm relying on the experts here as a cheat sheet..The problem is that I have 70 years of...
View ArticleRecursive CTE hiearchy snowflake -- join/ expand outward (columns) instead of...
I'm doing a dependency mapping explosion (like parts explosion).I did a typical recursive CTE with a union all.It looks likewith CTE as( select abc from myTable where start_point = Xunion allselect abc...
View ArticleUpgrade from Postgres 11 to Postgres 12 made some queries 300x slower,...
My application currently uses PostgreSQL 11.6. Today, I have tested PostgreSQL 12.1 on a virtual machine and the results were shocking:One important query which takes 100ms on version 11 (same VM) now...
View ArticleCan EXPLAIN be used to get some insights about Common Table Expression (CTE)?
I need to find the ancestors in a table having an ID value and a Google research point me to recursive Common Table Expression (CTE) I wonder if EXPLAIN can be used to get some insights on how MySQL...
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