Question

我来自这里[a link]的示例，它解释了如何编写递归查询。

WITH security_menu_Recursive(Parent,MenuId,MenuName,LEVEL)
AS
(
    SELECT vparent,vmenuid,vmenuname,0 AS LEVEL FROM dbo.SecurityMenu WHERE vParent = null
    UNION ALL
    SELECT vparent,vmenuid,vmenuname,Level + 1 AS LEVEL FROM dbo.SecurityMenu
    INNER JOIN security_menu_Recursive AS smr ON smr.menuid = dbo.SecurityMenu.vParent
)
SELECT parent,menuid,menuname,LEVEL FROM security_menu_Recursive

这对我来说很有用，但是我正在寻找从特定元组开始递归，在上面的示例中，例如从MenuId为102开始。

我尝试在三个SELECT中添加条件WHERE vmenuid = 102，但它没有用。

Answer 1

如果只是用vmenuid = 102条件替换锚的空检查，它应该可以正常工作;

WITH security_menu_Recursive(Parent,MenuId,MenuName,LEVEL)
AS
(
    SELECT vparent,vmenuid,vmenuname,0 AS LEVEL FROM dbo.SecurityMenu WHERE vMenuid=102
    UNION ALL
    SELECT vparent,vmenuid,vmenuname,Level + 1 AS LEVEL FROM dbo.SecurityMenu
    INNER JOIN security_menu_Recursive AS smr ON smr.menuid = dbo.SecurityMenu.vParent
)
SELECT parent,menuid,menuname,LEVEL FROM security_menu_Recursive

SQL Server - 从特定元组开始的递归

1 个答案: