Home Forums SQL Server 2012 SQL Server 2012 - T-SQL Build menu with CTE .... RE: Build menu with CTE ....

  • September 23, 2013 at 7:56 am

    #1652345

    hunchback (9/23/2013)

    I changed [path] by order_val in the recursive part and now it should run flawless.

    A recursive CTE is still an iterative approach so I do not hold my breath hoping for better performance.

    You can add a clustered index by ID and a nonclustered by IdRoot.

    Well said. Oddly enough, a well constructed WHILE loop that iterates over the Levels of the menu in a manner similar to the rCTE would probably do as well. In either case, the recursion is necessary and isn't as bad as an rCTE that counts because the rCTE method that we both used (and a similar WHILE loop would use) processes an entire set (all nodes at a given level) instead of just individual rows.

    --Jeff Moden

    RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
    First step towards the paradigm shift of writing Set Based code:
    ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

    Change is inevitable... Change for the better is not.

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