I have a table with records when some records are parents of other.
I have a column parent that with zero value means that is the parent. When is a child it has the id of the parent record.
What I need is to list the record by order, parent and childs.
My table TOOLS:
ID | order | parent | name
100 | 1 | 0 | X
200 | 2 | 0 | Y
150 | 0 | 100 | X.1
300 | 0 | 200 | Y.1
I need the following result:
ID | order | parent | name
100 | 1 | 0 | X
150 | 0 | 100 | X.1
200 | 2 | 0 | Y
300 | 0 | 200 | Y.1
How can I order this?
If I use this query
select t.*
from t
order by (case when parent = 0 then id else parent end), order desc;
The result is this:
ID | order | parent | name
200 | 2 | 0 | Y
300 | 0 | 200 | Y.1
100 | 1 | 0 | X
150 | 0 | 100 | X.1
And if I change the to order asc it put the records with order = 0 at the top...
Look this example
Thank you
You need to construct a value the provides the desired order. One way to do that is to construct a materialized path that encodes your order criteria. Since you are using SQL Server you could use its hierarchyid data type for this, however, the real magic is in building the materialized path itself, of which I'll show two versions, one used with the hierarchyid (path) and one without (path2):
with cte as (
-- Anchor Part
select id, [order], parent, name, 1 level
, cast('/'+cast(tools.id as varchar(10))+'/' as varchar(4000)) path
, cast(cast(tools.id as binary(4)) as varbinary(4000)) path2
from TOOLS
where parent = 0
union all
-- Recursive Part
select tools.*
, level+1
, cast(path+cast(tools.id as varchar(10))+'/' as varchar(4000))
, cast(path2+cast(tools.id as binary(4)) as varbinary(4000))
from tools
join cte
on tools.parent = cte.id
)
select id
, [order]
, parent
, name
, level
, path
, cast(path as hierarchyid) hid
, path2
from cte order by hid
In the above query, a recursive common table expression is used to walk the tree and build the two example paths. The first path, while it would work as a sort column on its own with your current IDs, would begin to fail as soon as you had IDs with a length other than three digits as the levels most significant digits would not necessarily align correctly. The cast to heirarchyid in the final query resolves that issue. The second path can be use directly as a sort key since it casts each level of the path to a four byte binary value, as such it can handle IDs up to 4,294,967,295 and path a length (tree depth) of 1000 levels and does not need a final cast to any other data types.
THIS ANSWERS THE ORIGINAL VERSION OF THE QUESTION.
In this case, you can use order by:
select t.*
from t
order by (case when parent = 0 then id else parent end), order desc;
Here is a SQL Fiddle that demonstrates that this works on your original question.
Related
*I apologize, my tables displayed correctly when I was writing this question and after publishing the formatting looks off. trying to fix that now
I am trying to write a query in postgresql that would return, for any given child value, the nearest parent value that has reached a certain rank. Currently, I have this query, which displays the entire hierarchical path for any given child value-
WITH RECURSIVE tree AS (
SELECT "ChildDisplayID",
"ParentID",
"Rank",
1 as level
FROM table1
WHERE "ChildDisplayID" = {{some ChildID}}
UNION ALL
SELECT t1."ChildDisplayID",
t1."ParentID",
t1."Rank",
t.level + 1
FROM table1 t1
JOIN tree t ON t."ParentID" = t1."ChildDisplayID"
)
SELECT *
FROM tree
What I want to do is have in a single row that displays the child ID and the parent ID of the nearest parent whose rank is "Partner". For example, here is the output I am currently getting:
| ChildID | ParentID | Rank | Level |
|---------|----------|------|-------|
| 6 | 5 |Associate Manager| 1 |
| 5 | 4 |Manager| 2 |
| 4 | 3 |Associate Partner| 3 |
| 3 | 2 |Partner| 4 |
| 2 | 1 |Partner| 5 |
| 1 | |CEO| 6 |
Here is the output I want:
|ChildID | Nearest Partner | Rank |
|--------|----------|------|
|6 |3 | Partner |
What is the best way to do this?
You can put a stop condition on the first matching partner in the recursion, then filter the result:
WITH RECURSIVE tree AS (
SELECT "ChildDisplayID" as initialid, "ChildDisplayID", "ParentID", "Rank", 1 as level
FROM table1
WHERE "ChildDisplayID" = {{some ChildID}}
UNION ALL
SELECT t.initialid, t1."ChildDisplayID", t1."ParentID", t1."Rank", t.level + 1
FROM table1 t1
INNER JOIN tree t ON t."ParentID" = t1."ChildDisplayID"
WHERE t."Rank" <> 'Partner'
)
SELECT *
FROM tree
WHERE "Rank" = 'Partner'
It seems like you have a hierarchy where each child has just one parent, so there should be only one match, or no match at all.
I want to write expressions in sqlite to process a tree of items, starting with the leaf nodes (the bottom) and proceeding back to their parents all the way to the root node (the top), such that each parent node is updated based on the content of its children. I've been able to write a CTE that does something similar, but isn't yet totally correct.
I have a simple table "test1" containing some nested values:
id | parent | value | total
---+--------+--------------
1 | NULL | NULL | NULL
2 | 1 | NULL | NULL
3 | 2 | NULL | NULL
4 | 3 | 50 | NULL
5 | 3 | 50 | NULL
6 | 2 | 60 | NULL
7 | 6 | 90 | NULL
8 | 6 | 60 | NULL
Rows may have children who reference their parent via their parent field. Rows may have a value of their own as well as child rows, or they may simply be parents without values (ie. "wrappers"). The leafs would be the rows without any children.
For each row I'd like to calculate the total, as the average or the row's value (if not null) AND its children's totals. This should start with the leaf nodes and proceed up the tree to their parents, all the way to the root node at the top of the data hierarchy.
I've tried a number of variations of CTE's but am having difficulty writing one that will recursively calculate these totals from the bottom up.
Currently, I have:
UPDATE test1 SET total = (
WITH RECURSIVE cte(cte_id,cte_parent,cte_value,cte_total) AS (
SELECT test1.id, test1.parent, test1.value, test1.total
UNION ALL
select t.id, t.parent, t.value, t.total from test1 t, cte
WHERE cte.cte_id=t.parent
) SELECT AVG(cte_value) FROM cte
);
which produces:
id | parent | value | total
---+--------+-------+------
1 | NULL | NULL | 62
2 | 1 | NULL | 62
3 | 2 | NULL | 50
4 | 3 | 50 | 50
5 | 3 | 50 | 50
6 | 2 | 60 | 70
7 | 6 | 90 | 90
8 | 6 | 60 | 60
Looking at the top-most rows, this is not quite right, since it's taking an average of not only the row's immediate children, but of all the row's descendants. This causes row 2 for example to have a total of 62 instead of 60. The expected results should set rows 2's total to 60, as the average of its immediate child rows 3 and 6. Row 1's total would be 60 as well.
How can I calculate a "total" value for each row based on an average of the row's value and the values of it's immediate children only, while ensuring the upper levels of the hierarchy are correctly populated based on the calculated totals of their children?
It turns out that a very similar question and solution was posted here:
How can I traverse a tree bottom-up to calculate a (weighted) average of node values in PostgreSQL?
Since sqlite3 doesn't let you create functions, the example using a recursive CTE applies:
with recursive cte(id, parent, value, level, total) as (
select
t.id, t.parent, t.value,
0,
t.value as total
from test1 t
where not exists (
select id
from test1
where parent = t.id)
union all
select
t.id, t.parent, t.value,
c.level+1,
case when t.value is null then c.total else t.value end
from test1 t
join cte c on t.id=c.parent
)
select id, parent, value, avg(total) total from (
select
id, parent, value, level, avg(total) total
from cte
group by id,parent,level
)
group by id, parent
order by id
I have a structure / tree that looks similar to this.
CostType is mandatory and can exist by itself, but it can have a parent ProfitType or Unit and other CostTypes as children.
There can only be duplicate Units. Other cannot appear multiple times in the structure.
| ID | name | parent_id | ProfitType | CostType | Unit |
| -: | ------------- | --------: |
| 1 | Root | (NULL) |
| 2 | 1 | 1 | 300 | | |
| 3 | 1-1 | 2 | | 111 | |
| 4 | 1-1-1 | 3 | | | 8 |
| 5 | 1-2 | 2 | | 222 | |
| 6 | 1-2-1 | 5 | | 333 | |
| 7 | 1-2-1-1 | 6 | | | 8 |
| 8 | 1-2-1-2 | 6 | | | 9 |
Parameters | should RETURN |
(300,111,8) | 4 |
(null,111,8) | 4 |
(null,null,8) | first match, 4 |
(null,222,8) | best match, 5 |
(null,333,null) | 6 |
I am at a loss on how I could create a function that receives (ProfitType, CostType, Unit) and return the best matching ID from the structure.
This isn't giving exactly the answers you provided as example, but see my comment above - if (null,222,8) should be 7 to match how (null,333,8) returns 4 then this is correct.
Also note that I formatted this using temp tables instead of as a function, I don't want to trip a schema change audit so I posted what I have as temp tables, I can rewrite it as a function Monday when my DBA is available, but I thought you might need it before the weekend. Just edit the "DECLARE #ProfitType int = ..." lines to the values you want to test
I also put in quite a few comments because the logic is tricky, but if they aren't enough leave a comment and I can expand my explanation
/*
ASSUMPTIONS:
A tree can be of arbitrary depth, but will not exceed the recursion limit (defaults to 100)
All trees will include at least 1 CostType
All trees will have at most 1 ProfitType
CostType can appear multiple times in a traversal from root to leaf (can units?)
*/
SELECT *
INTO #Temp
FROM (VALUES (1,'Root',NULL, NULL, NULL, NULL)
, (2,'1', 1, 300, NULL, NULL)
, (3,'1-1', 2, NULL, 111, NULL)
, (4,'1-1-1', 3, NULL, NULL, 8)
, (5,'1-2', 2, NULL, 222, NULL)
, (6,'1-2-1', 5, NULL, 333, NULL)
, (7,'1-2-1-1', 6, NULL, NULL, 8)
, (8,'1-2-1-2', 6, NULL, NULL, 9)
) as TempTable(ID, RName, Parent_ID, ProfitType, CostType, UnitID)
--SELECT * FROM #Temp
DECLARE #ProfitType int = NULL--300
DECLARE #CostType INT = 333 --NULL --111
DECLARE #UnitID INT = NULL--8
--SELECT * FROM #Temp
;WITH cteMatches as (
--Start with all nodes that match one criteria, default a score of 100
SELECT N.ID as ReportID, *, 100 as Score, 1 as Depth
FROM #Temp AS N
WHERE N.CostType= #CostType OR N.ProfitType=#ProfitType OR N.UnitID = #UnitID
), cteEval as (
--This is a recursive CTE, it has a (default) limit of 100 recursions
--, but that can be raised if your trees are deeper than 100 nodes
--Start with the base case
SELECT M.ReportID, M.RName, M.ID ,M.Parent_ID, M.Score
, M.Depth, M.ProfitType , M.CostType , M.UnitID
FROM cteMatches as M
UNION ALL
--This is the recursive part, add to the list of matches the match when
--its immediate parent is also considered. For that match increase the score
--if the parent contributes another match. Also update the ID of the match
--to the parent's IDs so recursion can keep adding if more matches are found
SELECT M.ReportID, M.RName, N.ID ,N.Parent_ID
, M.Score + CASE WHEN N.CostType= #CostType
OR N.ProfitType=#ProfitType
OR N.UnitID = #UnitID THEN 100 ELSE 0 END as Score
, M.Depth + 1, N.ProfitType , N.CostType , N.UnitID
FROM cteEval as M INNER JOIN #Temp AS N on M.Parent_ID = N.ID
)SELECT TOP 1 * --Drop the "TOP 1 *" to see debugging info (runners up)
FROM cteEval
ORDER BY SCORE DESC, DEPTH
DROP TABLE #Temp
I'm sorry I don't have enough rep to comment.
You'll have to define "best answer" (for example, why isn't the answer to null,222,8 7 or null instead of 5?), but here's the approach I'd use:
Derive a new table where ProfitType and CostType are listed explicitly instead of only by inheritance. I would approach that by using a cursor (how awful, I know) and following the parent_id until a ProfitType and CostType is found -- or the root is reached. This presumes an unlimited amount of child/grandchild levels for parent_id. If there is a limit, then you can instead use N self joins where N is the number of parent_id levels allowed.
Then you run multiple queries against the derived table. The first query would be for an exact match (and then exit if found). Then next query would be for the "best" partial match (then exit if found), followed by queries for 2nd best, 3rd best, etc. until you've exhausted your "best" match criteria.
If you need nested parent CostTypes to be part of the "best match" criteria, then I would make duplicate entries in the derived table for each row that has multiple CostTypes with a CostType "level". level 1 is the actual CostType. level 2 is that CostType's parent, level 3 etc. Then your best match queries would return multiple rows and you'd need to pick the row with the lowest level (which is the closest parent/grandparent).
Say, I have an organizational structure that is 5 levels deep:
CEO -> DeptHead -> Supervisor -> Foreman -> Worker
The hierarchy is stored in a table Position like this:
PositionId | PositionCode | ManagerId
1 | CEO | NULL
2 | DEPT01 | 1
3 | DEPT02 | 1
4 | SPRV01 | 2
5 | SPRV02 | 2
6 | SPRV03 | 3
7 | SPRV04 | 3
... | ... | ...
PositionId is uniqueidentifier. ManagerId is the ID of employee's manager, referring PositionId from the same table.
I need a SQL query to get the hierarchy tree going down from a position, provided as parameter, including the position itself. I managed to develop this:
-- Select the original position itself
SELECT
'Rank' = 0,
Position.PositionCode
FROM Position
WHERE Position.PositionCode = 'CEO' -- Parameter
-- Select the subordinates
UNION
SELECT DISTINCT
'Rank' =
CASE WHEN Pos2.PositionCode IS NULL THEN 0 ELSE 1+
CASE WHEN Pos3.PositionCode IS NULL THEN 0 ELSE 1+
CASE WHEN Pos4.PositionCode IS NULL THEN 0 ELSE 1+
CASE WHEN Pos5.PositionCode IS NULL THEN 0 ELSE 1
END
END
END
END,
'PositionCode' = RTRIM(ISNULL(Pos5.PositionCode, ISNULL(Pos4.PositionCode, ISNULL(Pos3.PositionCode, Pos2.PositionCode)))),
FROM Position Pos1
LEFT JOIN Position Pos2
ON Pos1.PositionId = Pos2.ManagerId
LEFT JOIN Position Pos3
ON Pos2.PositionId = Pos3.ManagerId
LEFT JOIN Position Pos4
ON Pos3.PositionId = Pos4.ManagerId
LEFT JOIN Position Pos5
ON Pos4.PositionId = Pos5.ManagerId
WHERE Pos1.PositionCode = 'CEO' -- Parameter
ORDER BY Rank ASC
It works not only for 'CEO' but for any position, displaying its subordinates. Which gives me the following output:
Rank | PositionCode
0 | CEO
... | ...
2 | SPRV55
2 | SPRV68
... | ...
3 | FRMN10
3 | FRMN12
... | ...
4 | WRKR01
4 | WRKR02
4 | WRKR03
4 | WRKR04
My problems are:
The output does not include intermediate nodes - it will only output end nodes, i.e. workers and intermediate managers which have no subordinates. I need all intermediate managers as well.
I have to manually UNION the row with original position on top of the output. I there any more elegant way to do this?
I want the output to be sorted in hieararchical tree order. Not all DeptHeads, then all Supervisors, then all Foremen then all workers, but like this:
Rank | PositionCode
0 | CEO
1 | DEPT01
2 | SPRV01
3 | FRMN01
4 | WRKR01
4 | WRKR02
... | ...
3 | FRMN02
4 | WRKR03
4 | WRKR04
... | ...
Any help would be greatly appreciated.
Try a recursive CTE, the example on TechNet is almost identical to your problem I believe:
http://technet.microsoft.com/en-us/library/ms186243(v=sql.105).aspx
Thx, everyone suggesting CTE. I got the following code and it's working okay:
WITH HierarchyTree (PositionId, PositionCode, Rank)
AS
(
-- Anchor member definition
SELECT PositionId, PositionCode,
0 AS Rank
FROM Position AS e
WHERE PositionCode = 'CEO'
UNION ALL
-- Recursive member definition
SELECT e.PositionId, e.PositionCode,
Rank + 1
FROM Position AS e
INNER JOIN HierarchyTree AS d
ON e.ManagerId = d.PositionId
)
SELECT Rank, PositionCode
FROM HierarchyTree
GO
I had a similar problem to yours on a recent project but with a variable recursion length - typically between 1 and 10 levels.
I wanted to simplify the SQL side of things so I put some extra work into the logic of storing the recursive elements by storing a "hierarchical path" in addition to the direct manager Id.
So a very contrived example:
Employee
Id | JobDescription | Hierarchy | ManagerId
1 | DIRECTOR | 1\ | NULL
2 | MANAGER 1 | 1\2\ | 1
3 | MANAGER 2 | 1\3\ | 1
4 | SUPERVISOR 1 | 1\2\4 | 2
5 | SUPERVISOR 2 | 1\3\5 | 3
6 | EMPLOYEE 1 | 1\2\4\6 | 4
7 | EMPLOYEE 2 | 1\3\5\7 | 5
This means you have the power to very quickly query any level of the tree and get all descendants by using a LIKE query on the Hierarchy column
For example
SELECT * FROM dbo.Employee WHERE Hierarchy LIKE '\1\2\%'
would return
MANAGER 1
SUPERVISOR 1
EMPLOYEE 1
Additionally you can also easily get one level of the tree by using the ManagerId column.
The downside to this approach is you have to construct the hierarchy when inserting or updating records but believe me when I say this storage structure saved me a lot of pain later on without the need for unnecessary query complexity.
One thing to note is that my approach gives you the raw data - I then parse the result set into a recursive strongly typed structure in my services layer. As a rule I don't tend to format output in SQL.
I need to create a view that automatically adds virtual row number in the result. the graph here is totally random all that I want to achieve is the last column to be created dynamically.
> +--------+------------+-----+
> | id | variety | num |
> +--------+------------+-----+
> | 234 | fuji | 1 |
> | 4356 | gala | 2 |
> | 343245 | limbertwig | 3 |
> | 224 | bing | 4 |
> | 4545 | chelan | 5 |
> | 3455 | navel | 6 |
> | 4534345| valencia | 7 |
> | 3451 | bartlett | 8 |
> | 3452 | bradford | 9 |
> +--------+------------+-----+
Query:
SELECT id,
variety,
SOMEFUNCTIONTHATWOULDGENERATETHIS() AS num
FROM mytable
Use:
SELECT t.id,
t.variety,
(SELECT COUNT(*) FROM TABLE WHERE id < t.id) +1 AS NUM
FROM TABLE t
It's not an ideal manner of doing this, because the query for the num value will execute for every row returned. A better idea would be to create a NUMBERS table, with a single column containing a number starting at one that increments to an outrageously large number, and then join & reference the NUMBERS table in a manner similar to the variable example that follows.
MySQL Ranking, or Lack Thereof
You can define a variable in order to get psuedo row number functionality, because MySQL doesn't have any ranking functions:
SELECT t.id,
t.variety,
#rownum := #rownum + 1 AS num
FROM TABLE t,
(SELECT #rownum := 0) r
The SELECT #rownum := 0 defines the variable, and sets it to zero.
The r is a subquery/table alias, because you'll get an error in MySQL if you don't define an alias for a subquery, even if you don't use it.
Can't Use A Variable in a MySQL View
If you do, you'll get the 1351 error, because you can't use a variable in a view due to design. The bug/feature behavior is documented here.
Oracle has a rowid pseudo-column. In MySQL, you might have to go ugly:
SELECT id,
variety,
1 + (SELECT COUNT(*) FROM tbl WHERE t.id < id) as num
FROM tbl
This query is off the top of my head and untested, so take it with a grain of salt. Also, it assumes that you want to number the rows according to some sort criteria (id in this case), rather than the arbitrary numbering shown in the question.