sql select parent child recursive in one field

Question

I do not know how to select query recursive..

 id     idparent    jobNO
--------------------------------
  1         0         1
  2         1         2
  3              


        

Answer 1

You need to use a Recursive Common Table Expression.

There are many useful articles online.

Useful Links

Simple Talk: SQL Server CTE Basics

blog.sqlauthority: Recursive CTE

Here is a solution to your question:

   CREATE TABLE #TEST
    (
        id int not null,
        idparent int not null,
        jobno int not null
    );

    INSERT INTO #Test VALUES 
    (1,0,1),
    (2,1,2),
    (3,1,3),
    (4,0,4),
    (5,4,5),
    (6,5,6);

    WITH CTE AS (
-- This is end of the recursion: Select items with no parent
        SELECT id, idparent, jobno, CONVERT(VARCHAR(MAX),jobno) AS ListJob
        FROM #Test
        WHERE idParent = 0
    UNION ALL
-- This is the recursive part: It joins to CTE
        SELECT t.id, t.idparent, t.jobno,  c.ListJob + '/' + CONVERT(VARCHAR(MAX),t.jobno) AS ListJob
        FROM #Test t
        INNER JOIN CTE c ON t.idParent = c.id
    )
    SELECT * FROM CTE
    ORDER BY id;