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TSQL - retrieve all IDs in a tree for a given subnode
I've tried to translate and implement the PostGres solution to the problem found here: PostgreSQL - retrieve all IDs in a tree for a given subnode, but I'm either programming it wrong, or...
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How can I efficiently traverse graph data with this pattern?
I have some relations embodying a directed acyclic graph that includes patterns similar to the following:I'm looking for an efficient way to traverse this graph data. Here is an example of the...
View ArticleWhat's the difference between a CTE and a Temp Table?
What is the difference between a Common Table Expression (CTE) and a temp table? And when should I use one over the other?CTEWITH cte (Column1, Column2, Column3)AS( SELECT Column1, Column2, Column3...
View ArticleMimicking a filesystem using PostgreSQL and LTree: how to write a query to...
I'm struggling with how to insert a recursive materialised path using one transaction.This is the situation:I'm trying to mimic a filesystem of folders and files. I have a table representing nodes...
View ArticleMysql8 Unable to order the result of WITH RECURSIVE query
I am using the WITH RECURSIVE query to generate a hierarchy of users. The data and the query used is shared in https://www.db-fiddle.com/f/oTbCcMQb5a4B6V96DAYJHG/0 . The query is returning the results...
View ArticleIs it possible to limit infinte recursion in an Oracle CTE?
In a DBMS like Microsoft SQL, there is a default limit of 100 recursions, in a recursive CTE, which can be adjusted with:WITH cte AS (…)SELECT * FROM cte OPTION (MAXRECURSION …);As far as I can tell,...
View Articleoracle working with CTE with condition
DEFINE fromtable1= true;WITH firstQuery AS ( SELECT columns FROM table),secondQuery AS ( SELECT columns FROM second_table) IF @fromtable1= true BEGIN SELECT * FROM firstQuery ENDELSE BEGIN SELECT *...
View ArticleHow can I recursively query a table containing LTREE to get the tree like...
Lets say I have this table:CREATE TABLE nodes (node_path ltree);INSERT INTO nodes VALUES ('Top.Science');INSERT INTO nodes VALUES ('Top.Science.Astronomy.Astrophysics');INSERT INTO nodes VALUES...
View ArticleWhy can't unused columns and tables be ignored in a recursive CTE
Usually, SQL Server can optimize away any unused columns in the execution plan, and unused joined tables are not queried. But as soon as a recursive CTE comes into play, apparently all columns and...
View ArticleHow do I calculate a streak of data and show the data that corresponds to it...
I'm currently working on a project with NBA stats and I want to check a player's longest streak of his highest amount of points on MySQL. I'm open to a 5-10 game streak to simplify it.For example:...
View ArticleRecursive CTE to find unique slug
I have an article table where I want the slug to be unique. CREATE TABLE article ( title char(50) NOT NULL, slug char(50) NOT NULL);When the user enters a title e.g. News on Apple, I want to check the...
View Articlecreating a CTE to filter previous CTE populaiton down. How to find new...
The first CTE grabs all patients with the diagnosis codes for substance abuse, the second CTE should filter down to only NEW paitents.Meaning of the people in the first CTE, which of thses people have...
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I want to make a tree of parents only in sql server
my table in databasehow can i get my result as Where child = 'chl1'
View ArticleDifference between a query based on CTE and a simple query
i'm doing a select starting from a table named events that is joined with device measurements using a date between function (this time between is a sort of "mobile windowing") in order to get the...
View ArticleOptimal way to get a total count of records in a paged query in Postgres?
I need to improve the performance of a paged query for customer orders in a Type2 Postgres db (always insert a new record with a new ID, the newest ID is the current version of the record). Changing...
View ArticleOptimal way to get a total count of rows in a paged query in Postgres?
I need to improve the performance of a paged query for customer orders in a Type2 Postgres db (always insert a new record with a new ID, the newest ID is the current version of the record). Changing...
View ArticleImplementing First In / First Out for fuel transactions (such as purchases at...
After being tasked with trying to improve the way my company keeps the fuel inventory, i hit a wall. My SQL knowledge is pretty basic and i don't even know where to start.A little background:The...
View ArticlePostgreSQL Query Performance: Sorting Array Length vs. CTE
I'm having a significant performance difference between two PostgreSQL queries that I'm trying to understand and optimize. I have a table with around 2TB of data, and both queries use the sequential...
View ArticleHow to reuse view logic with different date parameters?
Is there a way to reuse SQL logic behind a view by swapping justone DATE parameter?Below is a sample query with CTEs showing three levels of recordsin the example.erp schema:subscriptions --<...
View ArticlePerformance difference using CTE and subquery
I have run the following queries.CTEWITH temp AS (SELECT id, timestamp FROM table group by timestamp, id)SELECT COUNT(*) FROM temp WHERE timestamp = '2023-01-01 08:28:45'SubquerySELECT COUNT(*) FROM...
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