postgresql Recursive Update resulting in Sequential Scan
I have a table with a self-referential foreign key, and I would like to update a given parent, and all of the descendants of the parent, with the same recursive update.When using an UPDATE with a...
View ArticleUpdating table of versioned rows with historical records in PostgreSQL
I have a master table of versioned rows:CREATE TABLE master ( id SERIAL PRIMARY KEY, rec_id integer, val text, valid_on date[], valid_during daterange);INSERT INTO master (rec_id, val, valid_on,...
View ArticleDo I need an explicit FOR UPDATE lock in a CTE in UPDATE?
In Postgres 13, I have a table which gets updated frequently. However, the update query is rather complicated and uses the same values multiple times. So, using a CTE seems quite a logical thing to...
View ArticleHow can a cheap function in a SELECT make the whole query slow?
I'm using Postgres 13.3 with inner and outer queries that both only produce a single row (just some stats about row counts).I can't figure out why Query2 below is so much slower than Query1. They...
View ArticleDetail on MS SQL CTEs
I am trying to find out how MS CTEs actually access data. Trying to find out if CTEs will actually run slower when pulling data and what is the order that a CTE will pull data. Does a CTE pull the data...
View ArticleCTE get all descendants with parents
Schema:CREATE TABLE item ( id int primary key, parent_id int, FOREIGN KEY(parent_id) REFERENCES item(id));INSERT INTO item (id, parent_id)VALUES (1, NULL), (2, 1), (3, 1), (4, 2), (5, 3), (6, 3), (7,...
View Articleinsert the records after splitting the column values
Notes stored in the database as#AAA_FIRST, #AAA_SECOND_ENTRY, #AAA_THIRD, #AAA_FOURTH, #AAA_FIFTH_ENTRY.now i am trying to insert AAA in one table and FIRST , SECOND_ENTRY,THIRD,FOURTH,FIFTH_ENTRY in...
View ArticleOptimization : JOIN or CTE
Suppose that I have these tables,and example data (the real table I am working on has more columns)table `users`idnamezip1John201table `region`zipcitystatecountry22abctable...
View ArticleWhy should a CTE start with a semi-colon?
I was just looking at a post on StackOverflow where Aaron Bertrand proposes using a CTE instead of a numbers table, which is an elegant way of performing the task at hand. My question is, why does the...
View ArticleLooking for an alternative to a CTE that will work as a subquery in IF EXISTS
I have an IF EXISTS 'upsert' running fine by itself in it’s own stored proc. But when I try and use the same statement referencing a CTE, it doesn't recognize the CTE. I see in related post that I'm...
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Pivoting 4 by 44 result set
I have a SQL Server query that gets the sales data for a 44 store market chain, it includes 4 values for each store (Sales, COGS, GP and GP Margin), I declared a CTE and joined it 44 times for each...
View ArticlePostgres: Delete but keep x amount of rows per input
Let's say I have the following table, with data:+----+------+--------+------+| Id | User | Item | Time |+----+------+--------+------+| 1 | 1 | Banana | D+1 || 2 | 1 | Banana | D+2 || 3 | 1 | Banana |...
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 ArticleSELECT... with LIMIT, but iterate forward getting other records?
I am doing a SELECT * FROM... with LIMIT query inside of a LOOP in my pgplsql function/procedure - something like this, e.g.$$DECLAREBEGINLOOP exit when get diagnostics n_rec_count = 0; WITH cte_table...
View ArticlePostgres: After inserting value returns primary key and need to update column...
In a single query, I need to perform Insert and update on the insertion row. For example, I have a set of columns and its value to be inserted after getting the primary key, I need to update another...
View ArticleFiltering a recursive CTE as view
i'm using MSSQL Server 2017 and have a CTE used in a view to get the root element of a hirarchical tree linked to one specific element.If the CTE is used directly and the base elements are allready...
View ArticleDefine a function on the fly as with CTE in MySQL
With CTE it is possible to define 'on he fly' custom tables that exists only during the execution of the current query: is it possible to do the same for functions?Example use caseI have a query with...
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How to get text for default language
I have so tables:and so data at Language table:and so data at Text table:I have to return text for requested language if it exists and text for default language if it does not exist. Is it possible to...
View ArticleA query, safe against concurrent writes with READ COMMITTED, also safe with...
I have asked this question with a wonderfully informative answer:How to have uniqueness constraints for structures across multiple tables?The answer from Erwin Brandstetter suggests this:WITH...
View ArticleRECURSIVE CTE with INNER JOIN - Syntax Error
Can anyone help debug this less than informative error.You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'RECURSIVE...
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