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    <p>You can't do recursion in SQL without stored procedures. The way to solve this is using Nested Sets, they basically model a tree in SQL as a set.</p> <p>Notice that this will require a change to the current data model or possibly figuring out how to create a view on the original model.</p> <p>Postgresql example (using very few postgresql extensions, just SERIAL and ON COMMIT DROP, most RDBMSes will have similar functionality):</p> <p>Setup:</p> <pre><code>CREATE TABLE objects( id SERIAL PRIMARY KEY, name TEXT, lft INT, rgt INT ); INSERT INTO objects(name, lft, rgt) VALUES('The root of the tree', 1, 2); </code></pre> <p>Adding a child:</p> <pre><code>START TRANSACTION; -- postgresql doesn't support variables so we create a temporary table that -- gets deleted after the transaction has finished. CREATE TEMP TABLE left_tmp( lft INT ) ON COMMIT DROP; -- not standard sql -- store the left of the parent for later use INSERT INTO left_tmp (lft) VALUES((SELECT lft FROM objects WHERE name = 'The parent of the newly inserted node')); -- move all the children already in the set to the right -- to make room for the new child UPDATE objects SET rgt = rgt + 2 WHERE rgt &gt; (SELECT lft FROM left_tmp LIMIT 1); UPDATE objects SET lft = lft + 2 WHERE lft &gt; (SELECT lft FROM left_tmp LIMIT 1); -- insert the new child INSERT INTO objects(name, lft, rgt) VALUES( 'The name of the newly inserted node', (SELECT lft + 1 FROM left_tmp LIMIT 1), (SELECT lft + 2 FROM left_tmp LIMIT 1) ); COMMIT; </code></pre> <p>Display a trail from bottom to top:</p> <pre><code>SELECT parent.id, parent.lft FROM objects AS current_node INNER JOIN objects AS parent ON current_node.lft BETWEEN parent.lft AND parent.rgt WHERE current_node.name = 'The name of the deepest child' ORDER BY parent.lft; </code></pre> <p>Display the entire tree:</p> <pre><code>SELECT REPEAT(' ', CAST((COUNT(parent.id) - 1) AS INT)) || '- ' || current_node.name AS indented_name FROM objects current_node INNER JOIN objects parent ON current_node.lft BETWEEN parent.lft AND parent.rgt GROUP BY current_node.name, current_node.lft ORDER BY current_node.lft; </code></pre> <p>Select everything down from a certain element of the tree:</p> <pre><code>SELECT current_node.name AS node_name FROM objects current_node INNER JOIN objects parent ON current_node.lft BETWEEN parent.lft AND parent.rgt AND parent.name = 'child' GROUP BY current_node.name, current_node.lft ORDER BY current_node.lft; </code></pre>
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    1. POHow do I create a recursive query in MSSQL 2005?
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    1. USJasper Bekkers
    1. USJasper Bekkers
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    1. COBut you can, see mathieu's answer.
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      1. USMark S. Rasmussen
    2. COThe code I posted uses a technique applicable to any ANSI-SQL database because the OP forgot to mention the RDBMS he was using in his original post (see the comments for that post).
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