Below query is taking a lot of time to return results in two different databases. Is there any way to simplify this query?
WITH tblParent AS
(
SELECT *
FROM REFERENCES
WHERE referenced_id = 208593
UNION ALL
SELECT REFERENCES.*
FROM REFERENCES
JOIN tblParent ON REFERENCES.referenced_id = tblParent.entity_Id
)
SELECT DISTINCT(entity_Id)
FROM tblParent
WHERE entity_Id <> 208593 AND field_type = 'ChildField'
OPTION(MAXRECURSION 5)
This should simplify it:
WITH tblParent AS
(
SELECT entity_Id, 0 c
FROM [REFERENCES]
WHERE referenced_id = 208593
UNION ALL
SELECT r.entity_Id, 1
FROM [REFERENCES] r
JOIN tblParent
ON r.referenced_id = tblParent.entity_Id
)
SELECT DISTINCT entity_Id
FROM tblParent
WHERE c = 1
OPTION(MAXRECURSION 5)
By checking the c value, it becomes apparent that it is a child value. I am assuming that this text has field_type = 'ChildField' for all childs.
(REFERENCES is a reserved word and DISTINCT is not a function)
Since you're only interested in the child entityId's, then just select the fields you need in the recursive CTE.
WITH tblParent AS (
SELECT entity_Id, referenced_id as baseId
FROM [REFERENCES]
WHERE referenced_id = 208593
UNION ALL
SELECT t.entity_Id, cte.baseId
FROM tblParent cte
JOIN [REFERENCES] t
ON (t.referenced_id = cte.entity_Id
AND t.entity_Id <> cte.baseId -- to avoid a circular reference
)
WHERE t.field_type = 'ChildField'
)
SELECT DISTINCT entity_Id
FROM tblParent
WHERE entity_Id <> baseId
OPTION(MAXRECURSION 5)
And you might want to double-check if there's an index on referenced_id.
Related
I've two tables one of them called
Main-Level
another one called
Sub-level
Sub-level has a foreign key from the Main level (the relation between them Main-Level has one or Many Sub-levels )
what I want is to create a query to show the Main-level row followed by all Sub-level rows such as below screen-shot either by native SQL query or LINQ.
Update:
I used below but the problem is it the result such as Full OUTer JOIN !
select * from Sublevel
right join Mainlevel
on Sublevel.mainlevelID=Mainlevel.id
order by coalesce(Sublevel.mainlevelID, Mainlevel.id),
(case when Sublevel.mainlevelID is null then 1 else 0 end),Mainlevel.id;
Update 2:
Also, I tried below query but with no luck :
SELECT
s.name,
s.Id,
CASE WHEN s.is_child = 1 THEN s.parentID END AS parent_id,
m.name
FROM
Mainlevel m
INNER JOIN (
SELECT id, name, parentID, 1 AS is_child
FROM Sublevel
UNION ALL
SELECT id, name,Null, 0 AS is_child
FROM Mainlevel
) s on m.id = s.mainlevelID
ORDER BY m.id,is_child, s.mainlevelID
My problem in simple language is How to make the child rows appeared below parent row
The overall plan is to have parent join (parent + child) order by (parent ID, child ID)
SELECT
c.level_id,
c.level_name,
c.level_code,
CASE WHEN c.is_child = 1 THEN c.parent_id END AS parent_id,
FROM
mainLevel p
INNER JOIN (
SELECT level_id, level_name, level_code, parent_id, 1 AS is_child
FROM subLevel
UNION ALL
SELECT level_id, level_name, level_code, level_id, 0 AS is_child
FROM mainLevel
) c on p.level_id = c.parent_id
ORDER BY p.level_id, is_child, c.level_id
Additional version to adopt to the newly clarified column availability
SELECT
w.name,
w.id,
CASE WHEN w.is_child = 1 THEN w.mid END AS parent_id
FROM
Mainlevel m
INNER JOIN (
SELECT id, name, parentID AS mid, 1 AS is_child
FROM Sublevel
UNION ALL
SELECT id, name, id AS mid, 0 AS is_child
FROM Mainlevel
) w on m.id = w.mid
ORDER BY m.id, is_child, w.id
You can use order by:
order by coalesce(parentid, id),
(case when parentid is null then 1 else 0 end),
id
I am using TSQL.
If I have the following results:
And I want to transpose this to be like this:
How can I achieve this?
I have the following query:
WITH q AS (
SELECT *
FROM tableOne
WHERE ID = 1
UNION ALL
SELECT m.*
FROM tableOne m
JOIN ON m.ParentID = q.ID
)
SELECT *
FROM q
This gives me all of the items underneath the specified node including the specified node.
It could be easy for us to help you if you add scripting data and not an image. Note that tbl is the name of your table, it is called 3 times. Try this:
select
a.fieldValue company,
b.fieldValue department,
c.fieldValue Job
from tbl a
inner join tbl b on a.parentId is null and a.id=b.parentID
inner join tbl c on b.id= c.parentID
If it does not bring desired results please add data as text and let me know, I could modify the query
Another option (assuming this is NOT a jagged hierarchy).
This is a standard Recursive CTE, with a little twist in the final SELECT
Example
;with cteP as (
Select ID
,ParentID
,PathID = cast(FieldValue as varchar(max))
From YourTable
Where ParentID is Null
Union All
Select ID = r.ID
,ParentID = r.ParentID
,PathID = cast(p.PathID+'|||'+r.FieldValue as varchar(max))
From YourTable r
Join cteP p on r.ParentID = p.ID)
Select ID
,B.*
From cteP A
Cross Apply (
Select Company = xDim.value('/x[1]','varchar(max)')
,Department = xDim.value('/x[2]','varchar(max)')
,Job = xDim.value('/x[3]','varchar(max)')
From (Select Cast('<x>' + replace(PathID,'|||','</x><x>')+'</x>' as xml) as xDim) as X
) B
Where ID not in (Select Distinct ParentID from YourTable where ParentID is not null)
Order By PathID
Returns
For each row from table tClass matching a given where clause,
join on the first row in tEv, sorted by time, where tEv.class_id = tClass.class_id
The following code throws the error
ORA-01799: a column may not be outer-joined to a subquery
select
c.class_id,
c.class_name,
e.start_time,
e.ev_id
from
tClass c
left join tEv e on (
e.ev_id = (
select
ss1.ev_id
from (
select
ed.ev_id
from
tEvDisp ed,
tEv e
where
ed.class_id = c.class_id
and ed.viewable = 'Y'
and ed.display_until > localtimestamp
and e.ev_id = ed.ev_id
order by
e.start_time
) ss1
where
rownum = 1
)
)
where
c.is_matching = 'Y';
How can this be rewritten to do what is described?
The above is for oracle, but needs to work in sqlite (substituting where necessary)
No idea about SQLite - that would need to be a separate question if this doesn't work - but for Oracle you could do something like this:
select c.class_id,
c.class_name,
e.start_time,
e.ev_id
from tClass c
left join (
select class_id, ev_id, start_time
from (
select ed.class_id,
ed.ev_id,
e.start_time,
row_number() over (partition by ed.class_id order by e.start_time) as rn
from tEvDisp ed
join tEv e on e.ev_id = ed.ev_id
where ed.viewable = 'Y'
and ed.display_until > localtimestamp
)
where rn = 1
) e on e.class_id = c.class_id
where c.is_matching = 'Y';
This uses a subquery which finds the most tEv data, using an analytic row_number() to identify the latest data for each class_id, which is restricted by the rn = 1 filter.
That subquery, consisting of at most one row per class_id, is then used the left outer join against tClass.
This sort of construct should get you what you need. You can fix the details.
select c.classid
, c.classname
, temp.maxstarttime
from tClass c left join (
select c.classid id
max(e.start_time) maxstarttime
from tClass join tEv on tEv.classId = tClass.ClassId
where whatever
group by c.classid) temp on c.classid = temp.id
Given the following PostgreSQL table:
items
integer id
integer parent_id
string name
unique key on [parent_id, name]
parent_id is null for all root nodes
Currently I build the sql query manually, doing a join for every path element. But is seems quite ugly to me and of course it limits the possible depth.
Example:
path: holiday,images,spain
SELECT i3.*
FROM items AS i1
, items AS i2
, items AS i3
WHERE i1.parent_id IS NULL AND i1.name = 'holiday'
AND i2.parent_id=i1.id AND i2.name = 'images'
AND i3.parent_id=i2.id AND i3.name = 'spain'
I wonder if there's a better way, probably using CTE?
You can see how my current code works and what the expected output is here:
http://sqlfiddle.com/#!1/4537c/2
update2 here's a function, it peforms well, because search goes only within the path, starting from parent:
create or replace function get_item(path text[])
returns items
as
$$
with recursive cte as (
select i.id, i.name, i.parent_id, 1 as level
from items as i
where i.parent_id is null and i.name = $1[1]
union all
select i.id, i.name, i.parent_id, c.level + 1
from items as i
inner join cte as c on c.id = i.parent_id
where i.name = $1[level + 1]
)
select c.id, c.parent_id, c.name
from cte as c
where c.level = array_length($1, 1)
$$
language sql;
sql fiddle demo
update I think you can do recursive traversal. I've written sql version of this, so it's a bit messy because of cte, but it's possible to write a function:
with recursive cte_path as (
select array['holiday', 'spain', '2013'] as arr
), cte as (
select i.id, i.name, i.parent_id, 1 as level
from items as i
cross join cte_path as p
where i.parent_id is null and name = p.arr[1]
union all
select i.id, i.name, i.parent_id, c.level + 1
from items as i
inner join cte as c on c.id = i.parent_id
cross join cte_path as p
where i.name = p.arr[level + 1]
)
select c.*
from cte as c
cross join cte_path as p
where level = array_length(p.arr, 1)
sql fiddle demo
or you can build path for all of the elements using recursive cte for that and accumuate your path into array or string:
with recursive cte as (
select i.id, i.name, i.parent_id, i.name::text as path
from items as i
where i.parent_id is null
union all
select i.id, i.name, i.parent_id, c.path || '->' || i.name::text as path
from items as i
inner join cte as c on c.id = i.parent_id
)
select *
from cte
where path = 'holiday->spain->2013';
or
with recursive cte as (
select i.id, i.name, i.parent_id, array[i.name::text] as path
from items as i
where i.parent_id is null
union all
select i.id, i.name, i.parent_id, c.path || array[i.name::text] as path
from items as i
inner join cte as c on c.id = i.parent_id
)
select *
from cte
where path = array['holiday', 'spain', '2013']
sql fiddle demo
This should perform very well, as it eliminates impossible paths immediately:
WITH RECURSIVE cte AS (
SELECT id, parent_id, name
,'{holiday,spain,2013}'::text[] AS path -- provide path as array here
,2 AS lvl -- next level
FROM items
WHERE parent_id IS NULL
AND name = 'holiday' -- being path[1]
UNION ALL
SELECT i.id, i.parent_id, i.name
,cte.path, cte.lvl + 1
FROM cte
JOIN items i ON i.parent_id = cte.id AND i.name = path[lvl]
)
SELECT id, parent_id, name
FROM cte
ORDER BY lvl DESC
LIMIT 1;
Assuming you provide a unique path (only 1 result).
->SQLfiddle demo
Too late to post my answer (very equivalent to Roman's and Erwin's) But an improvement on the table definition instead:
CREATE TABLE items
( id integer NOT NULL PRIMARY KEY
, parent_id integer REFERENCES items(id)
, name varchar
, UNIQUE (parent_id,name) -- I don't actually like this one
); -- ; UNIQUE on a NULLable column ...
INSERT INTO items (id, parent_id, name) values
(1, null, 'holiday')
, (2, 1, 'spain'), (3, 2, '2013')
, (4, 1, 'usa'), (5, 4, '2013')
;
Create table #tmptble(RuleId, SubjectId, RID, Date)
Insert into #tmptble(RuleId,SubjectId, RID, Date)
Select RuleTable.RuleId, RuleTable.SubjectId, KeyTable.RID, KeyTable.ParentId
FROM RuleTable INNER JOIN KeyTable
ON KeyTable.RID = RuleTable.RID
This query is very slow. I have an clustered index on RID on KeyTable, clustered index on RuleId on RuleTable, Unique non clustered index on RuleId+SubjectId on the RuleTable. (RuleTable is used in various other places)
In the above query if I introduce a where clause like
Insert into #tmptble(RuleId,SubjectId, RID, Date)
Select RuleTable.RuleId, RuleTable.SubjectId, KeyTable.RID, KeyTable.ParentId
FROM RuleTable INNER JOIN KeyTable
ON KeyTable.RID = RuleTable.RID
WHERE KeyTable.RID = #RID -- #RID is passed into the storedproc
the running time reduces by > 50%. But the problem is that I use the original table result without the WHERE clause in the following way
WITH ResourceTree AS
(
SELECT
#tmptble.RuleId AS [RuleId],
#tmptble.SubjectId AS [SubjectRecId],
#tmptble.RId AS [RId],
#tmptble.ParentID AS [ParentID]
FROM #tmptble WHERE #tmptble.SubjectId = #SubjectId
AND #tmptble.RId = #RId
UNION ALL
-- Recursive step
-- Note that the recursive step uses the results from original #tmptable
SELECT
#tmptble.RuleId AS [RuleId],
#tmptble.SubjectId AS [SubjectId],
#tmptble.RId AS [RId],
#tmptble.ParentID AS [ParentID]
FROM #tmptble INNER JOIN ResourceTree RT
ON RT.ParentID = #tmptble.RId
)
SELECT *
FROM ResourceTree
Is there a way to optimize this query? Any kind of suggestions regarding indexes or way recursion is done would be helpful
Possible this be helpful for you -
;WITH temp AS
(
SELECT
r.RuleId
, r.SubjectId
, r.RID
, k.ParentId
FROM (
SELECT r.*
FROM dbo.RuleTable r
WHERE r.RID = #RID
) r
JOIN dbo.KeyTable k ON k.RID = r.RID
)
, ResourceTree AS
(
SELECT
t.RuleId
, [SubjectRecId] = t.SubjectId
, t.RId
, t.ParentID
FROM temp t
WHERE t.SubjectId = #SubjectId
UNION ALL
SELECT
t.RuleId
, t.SubjectId
, t.RId
, t.ParentID
FROM temp t
WHERE EXISTS (
SELECT 1
FROM ResourceTree r
WHERE r.ParentID = t.RId
)
)
SELECT *
FROM ResourceTree