Question

I am writing a stored procedure for retrieving the xml structure for a menu control. This seems to be a valid code( according to me & it is wrong) but does not run well on query tester. How could i correct it of the error below is the code

;WITH Hierarchy AS
(
    SELECT
        MenUid,MenuName,ApplicationId,ParentMenuId, 1 AS 'Level'
    FROM
        dbo.Menu
    WHERE
        ParentMenuId = '-1'

    UNION ALL

    SELECT
        M.MenUid,M.MenuName,M.ApplicationId,M.ParentMenuId, Level + 1 AS 'Level'
    FROM
        dbo.Menu M
    INNER JOIN
        Hierarchy h ON M.ParentMenuId = h.MenuId
)
SELECT *
FROM Hierarchy
ORDER BY [Level],[MenuName]

Where ParentMenuId and MenuId are related. Certain other doubts i got are below

1. Is this perfectly fine to use CTE for menu. What other types have you been successful
2. DataSet and ChildRelations are good too(or maybe i am wrong) for this purpose ?

Give me more ideas on how you have accomplished menu system in your projects.

Input

MenuId      MenuName      ApplicationId    ParentMenuId

 1          MenuName1           1              -1

 2          MenuName2           1               1

 3          MenuName3           1               -1

 4          MenuName4           1               2

Output

<Output>
    <Menu>
        <MenuId>1</MenuId>
        <MenuName>MenuName1</MenuName>
        <ApplicationId>1</ApplicationId>
        <ParentMenuId>-1</ParentMenuId>
        <SubMenu>
            <Menu>
                <MenuId>2</MenuId>
                <MenuName>MenuName2</MenuName>
                <ApplicationId>1</ApplicationId>
                <ParentMenuId>1</ParentMenuId>
                <SubMenu>
                    <MenuId>3</MenuId>
                    <MenuName>MenuName4</MenuName>
                    <ApplicationId>1</ApplicationId>
                    <ParentMenuId>3</ParentMenuId>
                </SubMenu>
            </Menu>
        </SubMenu>
    </Menu>
    <Menu>
        <MenuId>4</MenuId>
        <MenuName>MenuName3</MenuName>
        <ApplicationId>1</ApplicationId>
        <ParentMenuId>-1</ParentMenuId>
    </Menu>
</Output>

Don’t mind about the xml structure i is easy to get with FOR XML PATH i am not getting the query to run in the first place.

Answer 1

I’d wager that

INNER JOIN
    Hierarchy h ON M.ParentMenuId = h.ParentMenuId

should in fact be

INNER JOIN
    Hierarchy h ON M.ParentMenuId = h.MenuId

edit

Using this sample data:

declare @Menu table (
    MenuId int,
    MenuName nvarchar(20),
    ApplicationId int,
    ParentMenuId int
)

insert @Menu values
(1, 'Name1', 1, -1),
(2, 'Name2', 1,  1),
(3, 'Name3', 1, -1),
(4, 'Name4', 1,  2)

and your query, with the above modification, I get

MenUid      MenuName             ApplicationId ParentMenuId Level
----------- -------------------- ------------- ------------ -----------
1           Name1                1             -1           1
3           Name3                1             -1           1
2           Name2                1             1            2
4           Name4                1             2            3

which looks correct. To help you we need to see all your relevant code.