Databases
StackOverflow2013
Postsdbo
POPostgreSQL recursive with
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POPostgreSQL recursive with
    primarykey
    data
    text
    <p>I need help with a recursive query. Assuming the following table:</p> <pre><code>CREATE TEMPORARY TABLE tree ( id integer PRIMARY KEY, parent_id integer NOT NULL, name varchar(50) ); INSERT INTO tree (id, parent_id, name) VALUES (3, 0, 'Peter'), (2,0, 'Thomas'), (5,2, 'David'), (1, 0, 'Rob'), (8, 0, 'Brian'); </code></pre> <p>I can retrieve a list of all people and their children with the following query:</p> <pre><code>WITH RECURSIVE recursetree(id, parent_id) AS ( SELECT id, parent_id FROM tree WHERE parent_id = 0 UNION SELECT t.id, t.parent_id FROM tree t JOIN recursetree rt ON rt.id = t.parent_id ) SELECT * FROM recursetree; </code></pre> <p>How can I list them in order, and also sort the first level items by name? For example, the desired output would be:</p> <pre><code>id, parent_id, name 8, 0, "Brian" 3, 0, "Peter" 1, 0; "Rob" 2, 0, "Thomas" 5, 2, " David" </code></pre> <p>Thanks,</p> <p>**EDIT. Please note that adding an ORDER BY won't work: **</p> <pre><code>WITH RECURSIVE recursetree(id, parent_id, path, name) AS ( SELECT id, parent_id, array[id] AS path, name FROM tree WHERE parent_id = 0 UNION ALL SELECT t.id, t.parent_id, rt.path || t.id, t.name FROM tree t JOIN recursetree rt ON rt.id = t.parent_id ) SELECT * FROM recursetree ORDER BY path; </code></pre> <p>The above will retain the parent child relationship (children follow their parents), but applying any other ORDER BY clause (ie: name - like some have suggested) will cause the result to lose it's parent-child relationships.</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USrobdog
    1. USrobdog
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POPostgreSQL recursive with
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POPostgreSQL recursive with
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POPostgreSQL recursive with
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIsn't a simple ORDERBY doing the trick?
      singulars
      1. POPostgreSQL recursive with
      1. USMarcel Gheorghita
    2. COAn ORDER BY wouldn't place children under their parents, only order everything by name.
      singulars
      1. POPostgreSQL recursive with
      1. USrobdog
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload