SELECT and list children and parent

Question

I need a SQL query for the following COMPLEX task...

I need to to select from a column named parent_id. If a row has 0 for parent_id it means t

Answer 1

Using FOR XML EXPLICIT you can get a hierarchical list.

Try this:

SELECT 
 1 Tag,
 null Parent,
 '' [root!1!name],
 null [category!2!id],
 null [category!2!name],
 null [rule!3!id],
 null [rule!3!name]

UNION ALL 

SELECT DISTINCT 
 2 Tag,
 1 Parent,
 null,
 rule_id [category!2!id],
 rule_title [category!2!name],
 null [rule!3!id],
 null [rule!3!name]
FROM rules
WHERE parent_id = 0 and rule_type = 'cat'

UNION ALL 

SELECT  
 3 Tag,
 2 Parent,
 null,
 parent_id [category!2!id],
 null [category!2!name],
 rule_id [rule!3!id],
 rule_title [rule!3!name]
FROM rules
WHERE parent_id > 0 and rule_type = 'rule'

FOR XML EXPLICIT

For more information visit http://msdn.microsoft.com/en-us/library/ms189068.aspx