Questions tagged [recursive]

Using recursion to solve database problems.

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6
votes
2answers
3k views

Query to find circular references

I have two tables ID Task 1 1 2 2 3 3 4 4 Col1 depend 2 3 2 4 3 1 4 2 ID and Col1 are related through FK constraint. I want to find out all circular references. Here ID ...
12
votes
1answer
9k views

How do I sort the results of a recursive query in an expanded tree-like fashion?

Let's assume you have a nodes tables like this: CREATE TABLE nodes ( node serial PRIMARY KEY, parent integer NULL REFERENCES nodes(node), ts timestamp NOT NULL DEFAULT now() ); It ...
4
votes
1answer
5k views

Making a recursive CTE like query, but for many records

I have a table with a hierarchy ( with a recursive parentID column), for one record, I know how to get the last parent record, with the following code : declare @Id integer ;WITH CTE AS ( SELECT ...
1
vote
1answer
2k views

Self-join unique pairs

I have a table (players) containing a list of players, I would like to pair up these players in a unique way, so that every player's opponent is unique every round (ie. every time the SELECT query is ...
2
votes
2answers
409 views

SQL Server - Recursive “find all FK connections for ID through the entire DB” query

I'm dealing with a DB with hundreds of tables, with interconnecting FK references producing potentially thousands of different permutations for how for example table A and table K can join together. ...
2
votes
1answer
12k views

Recursive Query in MySQL using stored proceedure and CURSOR

I'm expanding our user/group system to allow for dynamic groups which are made up of other groups members. I have three tables users, groups, and relationships. For simplicity sake, lets say users ...
0
votes
1answer
913 views

Flatten recursive hierarchy

I have the following recursive query: SELECT SYS_CONNECT_BY_PATH(object_name, '\') AS path FROM user_group_nodes START WITH parent_id = '2892107544AA2278166C1AA8D123E761' CONNECT BY parent_id = PRIOR ...
2
votes
1answer
2k views

Tree structure hierarchical query sorting

I have the following structure of table. CREATE TABLE table1 ( serial_num integer NOT NULL, parent_num integer, parent_key text, key_ary_num integer[], level integer, rank integer, ...
2
votes
1answer
145 views

How do I query a table with many trees of data, for one tree?

I have a the NAICS schema loaded and all is working well. However I'm confused as how I'd query it in Postgrseql? The table looks something like this, =========NAICS_2012========= naics | ...
8
votes
1answer
4k views

Recursive CTE performance

Need help with recursive CTE performance. Below CTE is running very slow as it is trying to pull heirarchical data recusively. Table is big with every root id having upto 3 recursive itemid. There ...
33
votes
2answers
10k views

Using EXCEPT in a recursive common table expression

Why does the following query return infinite rows? I would have expected the EXCEPT clause to terminate the recursion.. with cte as ( select * from ( values(1),(2),(3),(4),(5) ) ...

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