SQL Server Equivalent of Oracle 'CONNECT BY PRIOR', and 'ORDER SIBLINGS BY'

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离开以前 2020-12-09 00:05

I\'ve got this Oracle code structure I\'m trying to convert to SQL Server 2008 (Note: I have used generic names, enclosed column names and tabl

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  • 2020-12-09 00:40

    The option given by the user "a_horse_with_no_name" worked for me. I changed the code and applied it to a menu generator query and it worked the first time. Here is the code:

    WITH tree(option_id,
           option_description,
          option_url,
          option_icon,
          option_level,
          sort_path)
         AS (
         SELECT ppo.option_id,
                ppo.option_description,
              ppo.option_url,
              ppo.option_icon,
              1 AS option_level,
              CAST('/' + RIGHT('00' + CONVERT(VARCHAR, ppo.option_index), 6) AS VARCHAR(MAX))
         FROM security.options_table_name ppo
         WHERE ppo.option_parent_id IS NULL
         UNION ALL
         SELECT co.option_id,
                co.option_description,
              co.option_url,
              co.option_icon,
              po.option_level + 1,
              po.sort_path + '/' + RIGHT('00' + CONVERT(VARCHAR, co.option_index), 6)
         FROM security.options_table_name co,
              tree AS po
         WHERE po.option_id = co.option_parent_id)
         SELECT *
         FROM tree
        ORDER BY sort_path;
    
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  • 2020-12-09 00:52

    to get dates for last 10 days:

    SELECT DISTINCT RecordDate = DATEADD(DAY,-number,CAST(GETDATE() AS DATE)) 
    FROM master..[spt_values] 
    WHERE number BETWEEN 1 AND 10
    
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  • 2020-12-09 00:54

    Simulating the LEVEL column

    The level column can easily be simulated by incrementing a counter in the recursive part:

    WITH tree (empid, name, level) AS  (
      SELECT empid, name, 1 as level
      FROM emp
      WHERE name = 'Joan'
    
      UNION ALL
    
      SELECT child.empid, child.name, parent.level + 1
      FROM emp as child
        JOIN tree parent on parent.empid = child.mgrid
    )
    SELECT name 
    FROM tree;
    

    Simulating order siblings by

    Simulating the order siblings by is a bit more complicated. Assuming we have a column sort_order that defines the order of elements per parent (not the overall sort order - because then order siblings wouldn't be necessary) then we can create a column which gives us an overall sort order:

    WITH tree (empid, name, level, sort_path) AS  (
      SELECT empid, name, 1 as level, 
             cast('/' + right('000000' + CONVERT(varchar, sort_order), 6) as varchar(max))
      FROM emp
      WHERE name = 'Joan'
    
      UNION ALL
    
      SELECT child.empid, child.name, parent.level + 1, 
             parent.sort_path + '/' + right('000000' + CONVERT(varchar, child.sort_order), 6) 
      FROM emp as child
        JOIN tree parent on parent.empid = child.mgrid
    )
    SELECT * 
    FROM tree
    order by sort_path;
    

    The expression for the sort_path looks so complicated because SQL Server (at least the version you are using) does not have a simple function to format a number with leading zeros. In Postgres I would use an integer array so that the conversion to varchar isn't necessary - but that doesn't work in SQL Server either.

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